vb.net console application program

2

'Simple Visual Basic program.

Module module1

Sub Main()

Console.WriteLine("Welcome to Visual Basic!")

End Sub ' Main

End Module

'Writing line of text with multiple statements

Module Tester1

Sub Main()

Console.Write("Welcome to ")

Console.WriteLine("Visual Basic!")

End Sub ' Main

End Module

'Every console app starts with Main

Module HelloWorld

Sub Main()

System.Console.WriteLine("Hello world!")

End Sub

End Module

'Read a single character

Module Module4

Sub Main()

Dim strChar As String

Console.Write("Enter a character: ")

strChar = Console.ReadKey.KeyChar

'strChar = Console.ReadKey(True).KeyChar

Console.WriteLine()

Console.WriteLine("You just entered {0}.", strChar)

End Sub

End Module

'Read a complete line of text

Module Module5

3

Sub Main()

Dim strLine As String

Console.Write("Enter a line of text: ")

strLine = Console.ReadLine

Console.WriteLine()

Console.WriteLine("You just entered: {0}", strLine)

End Sub

End Module

'Read a string from console

Module Module6

Sub Main()

Dim strMessage As String

Try

strMessage = Console.ReadLine()

Console.WriteLine("HELLO " + strMessage)

Catch ex As Exception

End Try

End Sub

End Module

'Use Do Loop to read user input

Module Module9

Sub Main()

Dim strInput As String

Do

Console.WriteLine("Please enter 'q' to quit...")

strInput = Console.ReadLine()

Console.WriteLine("You typed " & strInput)

Loop While (strInput <> "q")

Console.WriteLine("Quitting now.")

End Sub

End Module

'Use While to read user input

Module Module12

Sub Main()


Dim strInput As String = Console.ReadLine()

4

While (strInput <> "q")

Console.WriteLine("You typed " & strInput)


strInput = Console.ReadLine()

End While

Console.WriteLine("Quitting now.")

End Sub

End Module

'Output string to the Console

Module Module14

Sub Main()

Console.WriteLine("Hello from Module")

End Sub

End Module

'Variable index

Public Class Tester15

Public Shared Sub Main()

Console.WriteLine(String.Format("There are about {0}

days in {1} years.", 365.25 * 3, 3, 17))

End Sub

End Class

'Write some text based on the specified data type

Module Module16

Sub Main()

Console.Write(True)

Console.Write(25)

Console.Write("Some text.")

Console.WriteLine()

Console.WriteLine()

Console.WriteLine(True)

Console.WriteLine(25)

Console.WriteLine("Some text.")

End Sub

End Module

5

'Concatenate strings in Console.WriteLine statement

Module Module17

Sub Main()

Dim WebSite As String

Dim Publisher As String = "AAAA"

Console.WriteLine("AAAA: " & Publisher)

WebSite = "CCCC." & Publisher & ".DDDD"

Console.WriteLine("String one " & WebSite)

End Sub

End Module

'Reference variable index in Console.WriteLine

Module Module18

Sub Main()

Dim A As Double = 1.23456789

Console.WriteLine("{0} {1} {2}", 10, 2, 3)

End Sub

End Module

'Use Console.WriteLine to display various type variables

Module Module19

Sub Main()

Dim A As Integer = 100

Dim B As Double = 0.123456789

Dim Message As String = "Hello, VB World!"

Console.WriteLine(A)

Console.WriteLine("The value of A is " & A)

Console.WriteLine(B)

Console.WriteLine(B & " plus " & A & " = " & B + A)

Console.WriteLine(Message)

End Sub

End Module

6

'Demonstrates scope rules and instance variables


' instance variable can be used anywhere in class

Shared value As Integer = 1

' demonstrates class scope and block scope


Dim value As Integer = 5

Console.WriteLine("local variable value in" & "

FrmScoping_Load is " & value)

MethodA() ' MethodA has automatic local value

MethodB() ' MethodB uses instance variable value

MethodA() ' MethodA creates new automatic local value

MethodB() ' instance variable value retains its value

Console.WriteLine("local variable " & "value in

FrmScoping_Load is " & value)

End Sub

' automatic local variable value hides instance variable

Shared Sub MethodA()

Dim value As Integer = 25 ' initialized after each

call


MethodA is " & value & " after entering MethodA")

value += 1


MethodA is " & value & " before exiting MethodA")

End Sub

' uses instance variable value

Shared Sub MethodB()

Console.WriteLine("instance variable" & " value is " &

value & " after entering MethodB")

value *= 10

Console.WriteLine("instance variable " & "value is " &

value & " before exiting MethodB")

End Sub

End Class

7

'Block scope

Option Strict On

Public Class BlockScope


For outerLoop As Integer = 0 To 10000

For innerLoop As Integer = 0 To 10

Dim blockVar As Integer

blockVar += 1

If blockVar Mod 1000 = 0 Then

Console.WriteLine(blockVar)

End If

Next

Next

End Sub

End Class

'Variable block scope

Public Class Test22


For i As Integer = 1 To 5

Dim j As Integer = 3

If i = j Then

Dim M As Integer = i + j

Console.WriteLine("M: " & M)

Else

Dim N As Integer = i * j

Console.WriteLine("N: " & N)

End If

Dim k As Integer = 123

Console.WriteLine("k: " & k)

Next i

End Sub

End Class

'Variable scope in try catch statement

Public Class Test23


Try

Dim i As Integer = CInt("bad value")

Catch ex As InvalidCastException

Dim txt As String = "InvalidCastException"

Console.WriteLine(txt)


Dim txt As String = "Exception"


End Try

End Sub

End Class

8

'Define variable inside If statement

Public Class Test24


Dim manager As Boolean = True

If manager Then Dim txt As String = "M" :

Console.WriteLine(txt) Else _

Dim txt As String = "E" : Console.WriteLine(txt)

End Sub

End Class

'Sub scope()

Public Class Test25


DisplayHowardsName()

DisplayStephsName()

End Sub

Shared Sub DisplayStephsName()

Dim myName As String

myName = "A"

Console.WriteLine(myName)

End Sub

Shared Sub DisplayHowardsName()

Dim myName As String

myName = "B"

Console.WriteLine(myName)

End Sub

End Class

'Function local variables

Module Module26

Sub F()

Dim Name As String = "www.java2s.com"

Dim Price As Double = 17.45

Dim I As Integer = 1001

Console.WriteLine("In F")

Console.WriteLine("Name: " & Name)

Console.WriteLine("Price: " & Price)

Console.WriteLine("I: " & I)

End Sub

9

Sub FF()

Dim Name As String = "string"

Dim Price As Double = 49.99


Console.WriteLine("In FF")


Console.WriteLine("Price: " & Price)

Console.WriteLine("I: " & I)

End Sub

Sub Main()

F()

Console.WriteLine()

FF()

End Sub

End Module

'Local variable shadows global variable with the same name

Module Module27

Dim Counter As Integer

Sub BigLoop()

For Counter = 1000 To 1005 ' Use global Counter

Console.Write(Counter & " ")

Next

End Sub

Sub LittleLoop()

Dim Counter As Integer

For Counter = 0 To 5 ' Use local Counter

Console.Write(Counter & " ")

Next

End Sub

Sub Main()

Counter = 100

Console.WriteLine("Starting Counter: " & Counter)

BigLoop()

Console.WriteLine("Counter after BigLoop: " & Counter)

LittleLoop()

Console.WriteLine("Counter after LittleLoop: " &

Counter)

If (Counter > 1000) Then

Dim Counter As Integer = 0

10

Console.WriteLine("Counter in If statement: " & Counter)

End If

Console.WriteLine("Ending Counter: " & Counter)

End Sub

End Module

'Module global variable

Module Module29

Sub Main()

For intLoopIndex As Integer = 0 To 5

System.Console.WriteLine(Tracker())

Next intLoopIndex

End Sub

Dim intCount As Integer

Function Tracker() As Integer

intCount += 1

Return intCount

End Function

End Module

'class definition with namespace

Namespace WinForms

Public Class HelloWorld

Shared Sub Main()

System.Console.WriteLine("Hello World")

End Sub

End Class

End Namespace

'Define your own namespace

Namespace MyNamespace

Public Class Class2

End Class

End Namespace

Namespace MyNamespace

Public Class Class1

End Class

11

End Namespace

Module mod1

Sub main()

Dim objClass2 As MyNamespace.Class2

Dim objClass1 As MyNamespace.Class1

End Sub

End Module

'MUse Namespace

Namespace MyApp.Info

Module Main

Sub Main()

Dim objHW As New MyApp.Info.Utilities

objHW.DisplayData()

End Sub

End Module

Public Class Utilities

'Run the application

Public Sub DisplayData()

Console.WriteLine(Environment.MachineName)

Console.WriteLine(Environment.SystemDirectory)

Console.WriteLine(Environment.GetLogicalDrives())

Console.WriteLine(Environment.Version.ToString())

End Sub

End Class

End Namespace

'Use namespace to remove the conflicts

Namespace Network

Class Address

Public IP As String

Public DomainName As String

Public Sub New(ByVal IPAddr As String, ByVal Domain As

String)

IP = IPAddr

DomainName = Domain

End Sub

Public Sub ShowAddress()

Console.WriteLine("IP: " & IP)

Console.WriteLine("Domain: " & DomainName)

End Sub

End Class

End Namespace

12

Namespace Mailing

Class Address

Public Street As String

Public City As String

Public State As String

Public Zip As String

Public Sub New(ByVal Street As String, ByVal City As

String, ByVal State As String, ByVal Zip As String)

Me.Street = Street

Me.City = City

Me.State = State

Me.Zip = Zip

End Sub

Public Sub ShowAddress()

Console.WriteLine("Street: " & Street)

Console.WriteLine("City: " & City)

Console.WriteLine("State: " & State)

Console.WriteLine("Zip: " & Zip)

End Sub

End Class

End Namespace

Module Module32

Sub Main()

Dim IP As New Network.Address("122.111.222.112",

"www.SomeSite.com")

Dim address As New Mailing.Address("122 Main",

"Houston", "Texas", "77469")

IP.ShowAddress()

Console.WriteLine()

address.ShowAddress()

End Sub

End Module

'Static Variable

Option Strict On

Public Module Test33

Public Sub Main()

For loopCtr As Integer = 1 To 10

Console.WriteLine(Invocations())

Next

End Sub

13

Private Function Invocations() As Integer

Static i As Integer

i += 1

Return i

End Function

End Module

'Call static method

Option Strict On

Public Module CallStaticMethod

Public Sub Main()

Console.WriteLine(Greeting.SayHello())

End Sub

End Module

Public Class Greeting

Public Shared Function SayHello() As String

Return "And a top of the morning to you!"

End Function

End Class

'Cause compiler error when Option Strict On

Module Module36

Sub Main()

Dim AnInt As Integer = 5

Dim ALong As Long = 7

ALong = AnInt

'causes compiler error when Option Strict On

'AnInt = ALong

MsgBox(AnInt)

End Sub

End Module

'Option Explicit Off

Option Explicit Off

Module Explicit

Public Sub Main()

For ctr As Integer = 0 To 100

' Do something

result = cntr

Next

Console.WriteLine("The counter reached " & result &

".")

End Sub

End Module

14

'Turn Explicit off to use variable without declaration

Option Explicit Off

Module Module37

Sub Main()

EmployeeName = "Buddy Jamsa"

EmployeePhoneNumber = "555-1212"

EmployeeSalary = 45000.0

NumberOfEmployees = 1

Console.WriteLine("Number of employees: " &

NumberOfEmployees)

Console.WriteLine("Employee name: " & EmployeeName)

Console.WriteLine("Employee phone number: " &

EmployeePhoneNumber)

Console.WriteLine("Employee salary: " &

EmployeeSalary)

End Sub

End Module

'Hexadecimal Byte, UInteger and Integer

Option Strict On

Public Module modul38

Public Sub Main()

Dim maxValue As Byte = &HFF

Dim posValue As UInteger = &HF034

Dim negValue As Integer = &HF034

Console.WriteLine(maxValue)

Console.WriteLine(posValue)

Console.WriteLine(negValue)

End Sub

End Module

Public Class m39


Dim result As New System.Text.StringBuilder()

Dim maxByte As Byte = Byte.MaxValue

Dim maxSByte As SByte = SByte.MaxValue

Dim maxShort As Short = Short.MaxValue

Dim maxUShort As UShort = UShort.MaxValue

Dim maxInteger As Integer = Integer.MaxValue

Dim maxUInteger As UInteger = UInteger.MaxValue

15

Dim maxLong As Long = Long.MaxValue

Dim maxULong As ULong = ULong.MaxValue

Console.WriteLine("" & maxByte)

Console.WriteLine("" & maxSByte)

Console.WriteLine("" & maxShort)

Console.WriteLine("" & maxUShort)

Console.WriteLine("" & maxInteger)

Console.WriteLine("" & maxUInteger)

Console.WriteLine("" & maxLong)

Console.WriteLine("" & maxULong)

End Sub

End Class

'Swap two integers without using a third

Public Class m40


Dim firstValue As Integer

Dim secondValue As Integer

firstValue = 17

secondValue = 123

Console.WriteLine("Before swap: {0}, {1}", firstValue,

secondValue)

firstValue = firstValue Xor secondValue

secondValue = firstValue Xor secondValue

firstValue = firstValue Xor secondValue

Console.WriteLine("After swap: {0}, {1}", firstValue,

secondValue)

End Sub

End Class

'Parse Integer

Public Class m41


Try

Dim num_items As Integer = Integer.Parse("123")


Console.WriteLine(ex.Message)

End Try

End Sub

End Class

16

'Integer boolean calculation: Or, And, Xor, Not

Public Class m42


Dim I As Integer

I = 3 Or 4

Console.WriteLine(I)

I = 2 And 4


I = 3 Xor 3


I = Not 5


End Sub

End Class

'Use Integer.CompareTo to compare two integers

Public Class m43



Dim S As Integer = 8

Console.WriteLine(I.CompareTo(S))

End Sub

End Class

'Integer format: D10

Public Class m44


Dim intNumber As Integer = 12345

Console.WriteLine(intNumber.ToString("D10"))

End Sub

End Class

'Pass Integer to a function by reference

Module M45

Sub ParameterChange(ByRef A As Integer)

A = 1001

Console.WriteLine("Value of A in subroutine " & A)

End Sub

Sub Main()

Dim Number As Integer = 100

Console.WriteLine("Number before function call: " &

17

Number)

ParameterChange(Number)


Number)

End Sub

End Module

'Pass Integer to a function by value

Module M46

Sub NoChangeToParameter(ByVal A As Integer)

A = 1001

Console.WriteLine("Value of A in subroutine " & A)

End Sub

Sub Main()

Dim Number As Integer = 100


Number)

NoChangeToParameter(Number)


Number)

End Sub

End Module

'Compare Integer value in If statement

Module M47

Sub Main()

Dim TestScore As Integer = 80

If TestScore >= 90 Then

Console.WriteLine("Test grade: A")

ElseIf TestScore >= 80 Then

Console.WriteLine("Test grade: B")

ElseIf TestScore >= 70 Then

Console.WriteLine("Test grade: C")

Else

Console.WriteLine("Test grade: F")

End If

End Sub

End Module

18

'Integer OverflowException

Public Class m48


Dim A, B As Integer

Dim C As Integer

Try

A = 9999

B = 9999

C = A * B * B * B

Catch Except As OverflowException

Console.WriteLine("Overflow error detected")

End Try

End Sub

End Class

'Implicit conversion of an integer to a string

Module m49

Public Sub Main()

Dim iInteger As Integer = 5280

'Dim lLong As Long

'Dim bytByte As Byte

'Dim sngSingle As Single

'Dim dblDouble As Double

'Dim decDecimal As Decimal

Console.WriteLine("Implicit conversion of an integer

to a string: {0}", iInteger)

End Sub

End Module

'Explicit conversion of an integer to a string

Module m50

Public Sub Main()

Dim iInteger As Integer = 5280

'Dim lLong As Long

'Dim bytByte As Byte

'Dim sngSingle As Single

'Dim dblDouble As Double

'Dim decDecimal As Decimal

Console.WriteLine("Explicit conversion of an integer

to a string: {0}", CStr(iInteger))

End Sub

End Module

19

'Double.IsNaN()

Module M51

Sub Main()

If (Double.IsNaN("1.2")) Then

Console.WriteLine("Not a Number.")

End If

End Sub

End Module

'Double.IsNegativeInfinity()

Module MyModule52

Sub Main()

If (Double.IsNegativeInfinity("0.0000000000000001"))

Then

Console.WriteLine("Negative infinity.")

End If

End Sub

End Module

'Char.ToUpper

Public Class m53


Console.WriteLine(Char.ToUpper("a"))

End Sub

End Class

'vbNewLine

Public Class m54


Console.WriteLine("a" & vbNewLine & "b")

End Sub

End Class

'Concatenate vbTab with Integer

Option Strict On

Module M55

Sub Main()

Dim counter As Integer

20

For counter = 1 To 100

Console.Write("{0} ", counter)

If counter Mod 10 = 0 Then

Console.WriteLine(vbTab & counter)

End If

Next counter

End Sub

End Module

'Define Boolean value and use it in If statement

Public Class m56


Dim blnStatus As Boolean = True

Console.WriteLine(blnStatus)

blnStatus = Not blnStatus

Console.WriteLine(blnStatus)

If blnStatus Then

Console.WriteLine("The status is true.")

Else

Console.WriteLine("The status is false.")

End If

End Sub

End Class

'Define Enum and assign value

Module M57

Enum Temperatures

A = 0

B = 32

C = 60

D = 72

E = 212

End Enum

Sub Main()

System.Console.WriteLine("B: {0}", Temperatures.B)

System.Console.WriteLine("E: {0}", Temperatures.E)

End Sub

End Module

21

'Demonstrating overflows with and without checking

Class m58

Shared Sub Main()

Try

Dim number1 As Integer = Int32.MaxValue '

2,147,483,647

Dim number2 As Integer = Int32.MaxValue '

2,147,483,647

Dim sum As Integer = 0

Console.WriteLine("number1: {0}" & vbCrLf & _

"number2: {1}", number1, number2)

Console.WriteLine("Sum integers in checked

context:")

sum = number1 + number2 ' compute sum

Console.WriteLine("Sum after operation: {0}", sum)

Catch overflowExceptionParameter As OverflowException

Console.WriteLine(overflowExceptionParameter.ToString())

End Try

End Sub

End Class

'Join string

Public Class m59


Dim s() As String = {"one", "two", "three"}

'a string array

Dim s2 As String

s2 = String.Join(": ", s)

Console.WriteLine(s2)

End Sub

End Class

'Copy characters from string1 into character Array

Module m60

Sub Main()

Dim string1 As String

22

Dim characterArray As Char()

Dim i As Integer

Dim quotes As Char = ChrW(34)

string1 = "hello there"

characterArray = New Char(5) {}

string1.CopyTo(0, characterArray, 0, 5)

For i = 0 To characterArray.GetUpperBound(0)

Console.WriteLine(characterArray(i))

Next

End Sub ' Main

End Module

'String Length property

Module m61

Sub Main()

Dim string1 As String

'Dim characterArray As Char()

'Dim i As Integer


string1 = "hellothere"

'characterArray = New Char(5) {}

Console.WriteLine("Length of string1: " &

string1.Length)

End Sub ' Main

End Module

'Catch Exception for String.Substring

Public Class m62


Dim strCaption As String

strCaption = "Answer"

Try

Console.WriteLine(strCaption.Substring(10, 1))



End Try

End Sub

End Class

23

'Make a reference copy

Public Class m63


Dim arrayA() As String = {"One", "Two", "Three",

"Four", "Five", "Six"}

Console.WriteLine(Join(arrayA, ","))

Dim arrayB() As String = {"A", "B", "C", "D", "E",

"E", "F", "G", "H"}

Console.WriteLine(Join(arrayB, ","))

' ----- Make a reference copy.

Dim arrayC() As String = arrayA

Console.WriteLine(Join(arrayC, ","))

End Sub

End Class

'String Concatenate

Class m64


Dim s1 As String = "abcd"

Dim s2 As String = "ABCD"

' concatenation method

Dim s3 As String = String.Concat(s1, s2)

Console.WriteLine("s3 concatenated from s1 and s2:

{0}", s3)

End Sub 'Main

End Class 'Tester

'Use the overloaded operator

Class m65


Dim s1 As String = "abcd"

Dim s2 As String = "ABCD"

Dim s4 As String = s1 & s2

Console.WriteLine("s4 concatenated from s1 & s2:" +

s4)

End Sub 'Main

End Class 'Tester

24

'Array.Reverse a string array

Public Class m66


Dim StringArray() As String = {"This", "is", "a",

"test"}

Array.Reverse(StringArray)

Dim E As IEnumerator = StringArray.GetEnumerator()

While (E.MoveNext())

Console.WriteLine(E.Current())

End While

End Sub

End Class

'Comparing strings: Equals, =, String.Equals() and CompareTo

Module m67

Sub Main()

Dim string1 As String = "hello"

Dim string2 As String = "good bye"

Dim string3 As String = "Happy Birthday"

Dim string4 As String = "happy birthday"

'Dim output As String


If (string1.Equals("hello")) Then

Console.WriteLine("string1 equals hello")

Else

Console.WriteLine("not equal ")

End If

' test for equality with =

If string1 = "hello" Then

Console.WriteLine("string1 equals " & quotes &

"hello" & quotes)

Else

Console.WriteLine("string1 does not equal " &

quotes & "hello" & quotes)

End If

If (String.Equals(string3, string4)) Then

Console.WriteLine("string3 equals string4")

Else

25

Console.WriteLine("string3 does not equal

string4")

End If

' test CompareTo

'Console.WriteLine("string1.CompareTo(string2) is " &

_

' string1.CompareTo(string2) & vbCrLf & _

' "string2.CompareTo(string1) is " & _







' string4.CompareTo(string3))

Console.WriteLine("string1.CompareTo(string2) is ",

string1.CompareTo(string2))

'"string2.CompareTo(string1) is " & _

'string2.CompareTo(string1) & vbCrLf & _


'string1.CompareTo(string1) & vbCrLf & _


'string3.CompareTo(string4) & vbCrLf & _&


'string4.CompareTo(string3))

End Sub ' Main

End Module

'Demonstrating StartsWith and EndsWith methods

Module m68

Sub Main()

Dim strings As String()

Dim output As String = ""

Dim i As Integer


strings = New String() {"started", "starting", _

"ended", "ending"}

For i = 0 To strings.GetUpperBound(0)

If strings(i).StartsWith("st") Then

Console.WriteLine(" starts with st")

End If

Next

26

For i = 0 To strings.GetUpperBound(0)

If strings(i).EndsWith("ed") Then

Console.WriteLine(" ends with ed")

End If

Next

End Sub ' Main

End Module

'Replace a sub string with 'Replace'

Class m69

Shared Sub Main()

Dim userInput As String

userInput = " asdf "

Console.WriteLine(Replace(userInput, "f", ""))

End Sub

End Class

'Replace substring with another substring

Public Class m70


Dim s1 As New String("Greeting")

s1 = s1.Replace("e", "i")

Console.WriteLine(s1)

End Sub

End Class

'CInt

Public Class m71

Public Const MAX_VALUES As Integer = CInt(123.45)


End Sub

End Class

'Fix

'Option Strict On

Public Module FixTest

Public Sub Main()

Dim arr() As Decimal = {12.6D, 12.1D, -12.1D, -12.6D}

For Each num As Decimal In arr

Console.WriteLine("Fix({0}): {1}", num, Fix(num))

Console.WriteLine("Int({0}): {1}", num, Int(num))

Console.WriteLine()

Next

End Sub

End Module

27

'Compact operators

Public Class m73


Dim result As New System.Text.StringBuilder

Dim testDouble As Double = Math.PI

result.Append("Double ").AppendLine(testDouble)

testDouble += Math.PI

result.Append("+= ").AppendLine(testDouble)

testDouble *= Math.PI

result.Append("*= ").AppendLine(testDouble)

testDouble -= Math.PI

result.Append("-= ").AppendLine(testDouble)

testDouble /= Math.PI

result.Append("/= ").AppendLine(testDouble)

testDouble ^= Math.PI

result.Append("^= ").AppendLine(testDouble)

result.AppendLine()

Dim testInteger As Integer = 17

result.Append("Integer ").AppendLine(testInteger)

testInteger \= 2

result.Append("\= 2 ... ").AppendLine(testInteger)

testInteger += 1

result.Append("+= 1 ... ").AppendLine(testInteger)

testInteger <<= 1

result.Append("<<= 1 ... ").AppendLine(testInteger)

testInteger >>= 3

result.Append(">>= 3 ... ").AppendLine(testInteger)

result.AppendLine()

Dim testString As String = "Abcdef"

result.Append("String ").AppendLine(testString)

testString &= "ghi"

result.Append("&= ghi ... ").AppendLine(testString)

testString += "jkl"

result.Append("+= jkl ... ").AppendLine(testString)

Console.WriteLine(result.ToString())

End Sub

End Class

28

'Use logic operators in If statement: Not, And, Or

Module M74

Sub Main()

Dim A As Boolean = False

Dim B As Boolean = True

Dim C As Boolean = True

If (Not A) Then

Console.WriteLine("Not A")

End If

If (B Or C) Then

Console.WriteLine("B Or C")

End If

If (B And C) Then

Console.WriteLine("B And C")

End If

End Sub

End Module

'String is Like 'regular expressions *'

Public Class m75


Dim s As String

s = "VB.Net"

If s Like "*VB.Net" Then Console.WriteLine("'VB.Net'

is Like '*VB.Net'")

End Sub

End Class

'String is Like 'regular expressions ?' (question mark)

Public Class m76


Dim s As String

s = "VB.Net"

If s Like "?B.Net" Then Console.WriteLine("'VB.Net' is

Like '?B.Net'")

End Sub

End Class

29

'If with And

Imports System

Public Class m77

Shared Sub Main()

Dim dtCurrent As System.DateTime

Dim iHour As Integer

dtCurrent = Now

iHour = dtCurrent.Hour

If (iHour < 12) Then

Console.Writeline("Good Morning!")

ElseIf (iHour >= 12) And (iHour < 18) Then

Console.WriteLine("Good Afternoon!")

Else

Console.WriteLine("Good Evening!")

End If

End Sub

End Class

'Single line vs Multi-line If statement

Public Class m78


Dim intScore As Integer

intScore = 23

'Single line If statement.

If intScore < 50 Then Console.WriteLine("Failed.") :

Console.WriteLine("Please try again.")

'Multi-line If statement.

If intScore < 50 Then

Console.WriteLine("Failed.")

Console.WriteLine("Please try again.")

End If

End Sub

End Class

30

'IIf

Public Class m79


Dim intScore As Integer

intScore = 23

Console.WriteLine(IIf((intScore < 50), "fail",

"pass"))

End Sub

End Class

'Select Now.DayOfWeek

Public Class m80


Dim strMessage As String

Select Case Now.DayOfWeek

Case DayOfWeek.Monday

strMessage = "Have a nice week."

Case DayOfWeek.Friday

strMessage = "Have a nice weekend."

Case Else

strMessage = "Welcome back!"

End Select

Console.WriteLine(strMessage)

End Sub

End Class

'Use both range and fix value in Select statement

Module M81

Sub Main()

Dim intInput As Integer = 12

Select Case intInput

Case 1

Console.WriteLine("Thank you for the 1.")

Case 2 To 5

Console.WriteLine("Your value was 2, 3, 4, or

5")

Case Is > 5

Console.WriteLine("That was greater than 5.")

Case Else

Console.WriteLine("Sorry, I can't deal with

that.")

End Select

End Sub

End Module

31

'Specify several values in one Case statement

Public Class m82


Select Case "Bird"

Case "Bird"

Console.WriteLine("This animal has 2 legs.")

Case "Horse", "Dog", "Cat"


Case "Snake"

Console.WriteLine("This animal has no legs.")

Case "Centipede"


Case Else

Console.WriteLine("You did not select from the

list!")

End Select

End Sub

End Class

'Select Case statement with String range value

Option Strict On

Imports System

Module M83

Sub Main()

Dim target As String = "M"

Select Case target

Case "A" To "L"

Console.WriteLine("A To L executed")

Case "L" To "Z"

Console.WriteLine("L To Z executed")

Case Else

Console.WriteLine("Else executed")

End Select

End Sub 'Main

End Module

32

'Select Case statement with range Integer value

Option Strict On

Imports System

Module M84

Sub Main()

Dim targetInteger As Integer = 7

Select Case targetInteger

Case Is < 10

Console.WriteLine("Less than 10")

Case 10 To 14

Console.WriteLine("10-14")

Case 15

Console.WriteLine("15!")

Case Else

Console.WriteLine("Value not found")

End Select

End Sub 'Main

End Module

'Microsoft.VisualBasic.Switch

Module M85

Sub Main()

Dim intValue As Integer = -10

Console.WriteLine("Absolute value: " & _

Microsoft.VisualBasic.Switch(intValue < 0, -1 *

intValue, intValue >= 0, intValue))

End Sub

End Module

'For loop with float point control number

Option Strict On

Imports System

Module M86

Sub Main()

Dim loopCounter As Single

For loopCounter = 0.5 To 9

Console.WriteLine("loopCounter: {0}", loopCounter)

Next

End Sub 'Main

33

End Module

'Set For Loop float Step

Option Strict On

Imports System

Module M87

Sub Main()

Dim loopCounter As Single

For loopCounter = 0.5 To 9 Step 0.5

Console.WriteLine("loopCounter: {0}", loopCounter)

Next

End Sub 'Main

End Module

'Use For Each to loop through Array

Option Strict On

Imports System

Public Class Employee3

Private empID As Integer

Public Sub New(ByVal empID As Integer)

Me.empID = empID

End Sub

Public Overrides Function ToString() As String

Return empID.ToString()

End Function

End Class

Class m88

Shared Sub Main()

Dim intArray() As Integer

Dim empArray() As Employee3

intArray = New Integer(5) {}

empArray = New Employee3(3) {}

Dim i As Integer

For i = 0 To empArray.Length - 1

empArray(i) = New Employee3(i + 5)

Next i

Console.WriteLine("The Integer array...")

34

Dim intValue As Integer

For Each intValue In intArray

Console.WriteLine(intValue.ToString())

Next

Console.WriteLine("The employee array...")

Dim e As Employee3

For Each e In empArray

Console.WriteLine(e)

Next

End Sub 'Run

End Class

'Exit For

Public Class m89


Dim j As Integer


j = 0

Do While j < 3

j += 1

For k As Integer = 1 To 3

Dim test1 As Boolean = k = 2

If test1 Then Exit For ' Exits the For K

loop.

Dim test2 As Boolean = i = j

If test2 Then Exit Do ' Exits the Do.

Console.WriteLine(i & ", " & j & ", " & k)

Next k

Loop

Next i

End Sub

End Class

'Continue Do

Public Class m90


Dim j As Integer


j = 0

Do While j < 3

j += 1

For k As Integer = 1 To 3

Dim test1 As Boolean = k = 2

If test1 Then Continue For ' Continues the

For K loop.

Dim test2 As Boolean = i = j

If test2 Then Continue Do ' Continues the

35

Do.

Console.WriteLine(i & ", " & j & ", " & k)

Next k

Loop

Next i

End Sub

End Class

'GoTo statement with Label

Option Strict On

Imports System

Module M91

Sub Main()

Dim counterVariable As Integer = 0

repeat:

Console.WriteLine("counterVariable: {0}",

counterVariable)

counterVariable += 1

If counterVariable < 10 Then

GoTo repeat

End If

End Sub

End Module

'Imports System

Module m92

Enum Medal As Short

Gold

Silver

Bronze

End Enum

Sub Main()

Dim myMedal As Medal = Medal.Bronze

Console.WriteLine("My medal: " & myMedal.ToString)

End Sub

End Module

'Imports command

Imports System

Public Class Step2

Shared Sub Main()

Console.WriteLine("info")

End Sub

End Class

36

'On Error GoTo errorhandle

Imports System.IO.File

Public Class m94


Dim myfile As System.IO.File

Dim w As System.IO.StreamWriter

On Error GoTo errorhandle

w = myfile.AppendText("a:\temp.txt")

w.Write("a")

w.Close()

Exit Sub

errorhandle:

Console.WriteLine("Please Insert")

Exit Sub

Resume

End Sub

End Class

'Select Case Err.Number

Imports System.IO

Public Class m95


On Error GoTo ErrorHandle

Exit Sub

ErrorHandle:

Select Case Err.Number

Case 52

Console.WriteLine("File Name Exception")

Case 53

Console.WriteLine("File cannot be found")

Case 54

Console.WriteLine("File Mode Exception")

Case 55

Console.WriteLine("File is aleady open")

Case 58

Console.WriteLine("File exists")

Case 68

Console.WriteLine("Device is not available")

37

Case 75

Console.WriteLine("Path Exception")

Case 76

Console.WriteLine("Path cannot be found")

Case Else

Console.WriteLine("Other")

End Select

End Sub

End Class

'Resume

Module M96

Sub Main()

On Error GoTo Handler

Dim i1 As Integer = 0

Dim i2 As Integer = 128

Dim intResult As Integer

intResult = i2 / i1

Console.WriteLine("Press Enter to continue...")

Console.ReadLine()

Exit Sub

Handler:

Console.WriteLine("An overflow error occurred.")

Resume Next

End Sub

End Module

'Add Time to current time

Public Class m97


Dim rightNow As Date = Now

Console.WriteLine("RightNow: " & rightNow.ToString)

' ----- Add time values.

Console.WriteLine("RightNow.AddHours(5): " &

rightNow.AddHours(5))

Console.WriteLine("RightNow.AddMinutes(6): " &

rightNow.AddMinutes(6))

Console.WriteLine("RightNow.AddSeconds(7): " &

rightNow.AddSeconds(7))

Console.WriteLine("RightNow.AddMilliseconds(8000): " &

rightNow.AddMilliseconds(8000))

End Sub

End Class

38

'Elapsed Ticks

Public Class m98


Dim ticksBefore As Long

Dim ticksAfter As Long

Dim tickSeconds As Double

ticksBefore = Now.Ticks

MsgBox("Press OK to see elapsed seconds")

ticksAfter = Now.Ticks

tickSeconds = (ticksAfter - ticksBefore) / 10000000.0

Console.WriteLine("Elapsed seconds: " &

tickSeconds.ToString())

End Sub

End Class

'Subtract Time

Public Class m99


Dim results As New System.Text.StringBuilder


results.AppendLine("RightNow: " & rightNow.ToString)

results.AppendLine()

results.AppendLine("One year ago: " & _

rightNow.AddYears(-1).ToString)

results.AppendLine("365.25 days ago: " & _

rightNow.AddDays(-365.25).ToString)

Console.WriteLine(results.ToString())

End Sub

End Class

'System Time

39

Public Class m100




result.AppendLine("""Now""...")

result.AppendLine()

result.Append("Date:

").AppendLine(rightNow.ToShortDateString)

result.Append("Time:

").AppendLine(rightNow.ToShortTimeString)

result.Append("Ticks:

").Append(rightNow.Ticks.ToString)


End Sub

End Class

'Date and TimeSpan

Public Class Test


Dim date1 As Date = #7/20/2004#

Dim date2 As Date = #8/21/2004#

Dim elapsed_time As TimeSpan

elapsed_time = Date.op_Subtraction(date2, date1)

Console.WriteLine(elapsed_time.Days.ToString)

End Sub

End Class

'Get Ticks from DateTime

Public Class m102


Console.WriteLine("Ticks since 12:00AM January 1, 1

CE=" + Now().Ticks().ToString())

40

End Sub

End Class

'Compare Date value in If statement

Module M103

Sub Main()

If (Now.Hour < 12) Then

Console.WriteLine("Good morning")

ElseIf (Now.Hour < 18) Then

Console.WriteLine("Good day")

Else

Console.WriteLine("Good evening")

End If

End Sub

End Module

'Select Day Of Week

Module M104

Sub Main()

Dim DayOfWeek As Integer

DayOfWeek = Now.DayOfWeek

Select Case DayOfWeek

Case 1

Console.WriteLine("Sunday")

Case 2

Console.WriteLine("Monday")

Case 3

Console.WriteLine("Tuesday")

Case 4

Console.WriteLine("Wednesday")

41

Case 5

Console.WriteLine("Thursday")

Case 6

Console.WriteLine("Friday")

Case 7

Console.WriteLine("Saturday")

End Select

End Sub

End Module

'Use format specifiers to control the date display

Public Class m105




result.AppendLine("""Now""...")

' ----- Use format specifiers to control the date

display.

result.Append("d:

").AppendLine(rightNow.ToString("d"))

result.Append("D:

").AppendLine(rightNow.ToString("D"))

result.Append("t:

").AppendLine(rightNow.ToString("t"))

result.Append("T:

").AppendLine(rightNow.ToString("T"))

result.Append("f:

").AppendLine(rightNow.ToString("f"))

result.Append("F:

").AppendLine(rightNow.ToString("F"))

result.Append("g:

").AppendLine(rightNow.ToString("g"))

result.Append("G:

").AppendLine(rightNow.ToString("G"))

result.Append("M:

").AppendLine(rightNow.ToString("M"))

result.Append("R:

").AppendLine(rightNow.ToString("R"))

result.Append("s:

").AppendLine(rightNow.ToString("s"))

result.Append("u:

42

").AppendLine(rightNow.ToString("u"))

result.Append("U:

").AppendLine(rightNow.ToString("U"))

result.Append("y:

").AppendLine(rightNow.ToString("y"))

Console.WriteLine(result.ToString)

End Sub

End Class

'Date format: dd

Public Class m106




result.Append("dd:

").AppendLine(rightNow.ToString("dd"))


End Sub

End Class

'Date format: ddd

Public Class m107




result.Append("ddd:

").AppendLine(rightNow.ToString("ddd"))


End Sub

End Class

43

'Date format: dddd

Public Class m108




result.Append("dddd:

").AppendLine(rightNow.ToString("dddd"))


End Sub

End Class

'Date format: HH:mm:ss.fff z

Public Class m109




result.Append("HH:mm:ss.fff z: ")

result.AppendLine(rightNow.ToString("HH:mm:ss.fff z"))


End Sub

End Class

'Date format: {0:MMMM-dd-yy HH:mm:ss}

44

Public Class m110


Console.WriteLine(DateTime.Now.ToString)

Console.WriteLine(String.Format("{0:MMMM-dd-yy

HH:mm:ss}", DateTime.Now))

End Sub

End Class

'DateAdd: add two date together

Option Strict On

Public Module DateAddTest

Public Sub Main()

Console.WriteLine(DateAdd(DateInterval.Hour, 36,

Date.Now))

Console.WriteLine(DateAdd(DateInterval.Hour, -36,

Date.Now))

End Sub

End Module

'Different date between two dates

Public Class m112


'Dim dteExpiration As Date

Dim lngDays As Long

lngDays = DateDiff(DateInterval.Day, #12/31/2000#,

Now())

Console.WriteLine(lngDays)

End Sub

End Class

45

'TimeOfDay

Public Class m113


Console.WriteLine(TimeOfDay)

End Sub

End Class

'Different parts of Now

Public Class m114



Dim hourNow As Integer = rightNow.Hour

Dim minuteNow As Integer = rightNow.Minute

Dim secondNow As Integer = rightNow.Second

Dim millisecondNow As Integer = rightNow.Millisecond

Dim results As String = String.Format( _

"Hour: {1}{0}Minute: {2}{0}Second: " & _

"{3}{0}Millisecond: {4}", vbNewLine, _

hourNow, minuteNow, secondNow, millisecondNow)

Console.WriteLine(results)

End Sub

End Class

'Use StopWatch

Public Class m115


Dim testWatch As New System.Diagnostics.Stopwatch

Dim results As String

46

' ----- Start counting.

testWatch.Start()

MsgBox("Press OK to see elapsed seconds")

' ----- Stop and record.

results = String.Format( _

"testWatch.Elapsed.Seconds: {0}{3}" & _

"testWatch.Elapsed.TotalSeconds: {1}{3}" & _

"testWatch.ElapsedMilliseconds / 1000: {2}", _

testWatch.Elapsed.Seconds, _

testWatch.Elapsed.TotalSeconds, _

testWatch.ElapsedMilliseconds / 1000, vbNewLine)


End Sub

End Class

'Date different parts

Public Class m116



Dim yearNow As Integer = rightNow.Year

Dim monthNow As Integer = rightNow.Month

Dim dayNow As Integer = rightNow.Day

Dim results As String = String.Format( _

"Year: {1}{0}Month: {2}{0}Day: {3}{0}", _

vbNewLine, yearNow, monthNow, dayNow)


End Sub

End Class

'Day of the week

Public Class m117


Console.WriteLine(Today.DayOfWeek.ToString())

End Sub

End Class

47

'TimeSpan and Date Substract

Public Class m118


Dim birthDay As Date

Dim lifeTime As TimeSpan

Dim lifeDays As Integer

birthDay = Date.Parse("December 25, 2007")

lifeTime = Now.Subtract(birthDay)

lifeDays = lifeTime.Days

Console.WriteLine(String.Format( _

"There are {0} days between {1:D} and {2:D}", _

lifeDays, birthDay, Now))

End Sub

End Class

'Define a sub routine and call it

Option Strict On

Imports System

Module m119

Sub Main()

Console.WriteLine("In Main! ")

SomeMethod()

Console.WriteLine("Back in Main( ).")

End Sub 'Main

Sub SomeMethod()

Console.WriteLine("Greetings from SomeMethod!")

End Sub

End Module

'Sub procedure that prints payment information.

48

Module m120

Sub Main()

PrintSub(40, 10.5)

PrintSub(38, 21.75)

PrintSub(20, 13)

PrintSub(50, 14)

End Sub

Sub PrintSub(ByVal hours As Double, ByVal wage As Decimal)

Console.WriteLine("The payment is {0:C}", hours *

wage)

End Sub

End Module

'Define function in a Module

Module M121

Const Sale As Decimal = 100

Const TaxRate As Decimal = 0.04D

Function GetTotalSale() As Decimal

Return Sale * (1 + TaxRate)

End Function

Sub Main()

Dim TotalSale As Decimal = GetTotalSale()

Console.WriteLine(TotalSale)

End Sub

End Module

'Function with string return

49

Public Class m122


Dim strISBN As String = "078212283"

Console.WriteLine("The check Digit is " &

ISBNCheckDigit("078212283") & ".")

Console.WriteLine("The complete ISBN is " & strISBN &

ISBNCheckDigit(strISBN) & ".")

End Sub

Shared Function ISBNCheckDigit(ByVal strISBN As String) As

String

Dim i, intCheckSum, intCheckDigit As Integer

For i = 0 To 8

intCheckSum = intCheckSum + (10 - i) *

strISBN.Substring(i, 1)

Next

intCheckDigit = 11 - (intCheckSum Mod 11)

If intCheckDigit = 10 Then

Return ("X")

Else

Return (intCheckDigit.ToString)

End If

End Function

End Class

'Return double type value from Function

Public Class m123


Console.WriteLine(ComputeSalesTax(34.34, 0.07))

End Sub

Shared Function ComputeSalesTax(ByVal amount As Double, _

ByVal tax As Single) As Double

Return amount * tax

50

End Function

End Class

'Define function and call it in a Module

Module M124

Sub ShowBookInformation()

Console.WriteLine("A")

Console.WriteLine("B")

Console.WriteLine("C")

Console.WriteLine("D")

End Sub

Sub GreetInEnglish()

Console.WriteLine("Hello, world")

End Sub

Sub GreetInSpanish()

Console.WriteLine("Hola, mundo")

End Sub

Sub ShowTime()

Console.WriteLine("Current time is: " & Now)

End Sub

Sub Main()

ShowTime()

GreetInEnglish()

GreetInSpanish()

ShowBookInformation()

End Sub

End Module

'Finds the maximum of three numbers input

51

Module m125

Sub Main()

Dim value1, value2, value3 As Double

value1 = 1.1

value2 = 2.2

value3 = 3.3

Console.WriteLine(Maximum(value1, value2, value3))

End Sub

Function Maximum(ByVal valueOne As Double, _

ByVal valueTwo As Double, ByVal valueThree As Double) _

As Double

Return Math.Max(Math.Max(valueOne, valueTwo),

valueThree)

End Function

End Module

'Optional parameters

Module M126

Sub Main()

ShowMessage()

End Sub

Sub ShowMessage(Optional ByVal strText As String = "Hello

there!")

System.Console.WriteLine(strText)

End Sub

End Module

'Argument Order

52

Imports System

Public Module m127

Public Function Add(ByVal Num1 As Integer, ByVal Num2 As

Double) As Double

Return Num1 + Num2

End Function

Public Function Add(ByVal Num2 As Double, ByVal Num1 As

Integer) As Double

Return Num1 - Num2

End Function

Sub Main()

Dim Num3 As Double = Add(2, 4.2)

Dim Num4 As Double = Add(4.2, 2)

Console.WriteLine("The first Add Method " & Num3)

Console.WriteLine("The Second Add Method " & Num4)

End Sub

End Module

'Demonstrates passing by reference.

Module m128

Sub Main()

Dim number1 As Integer = 2

Console.WriteLine("Before calling SquareByValue, " &

"number1 is {0}", number1)

SquareByValue(number1) ' passes number1 by value

Console.WriteLine("After returning from SquareByValue,

" & "number1 is {0}" & vbCrLf, number1)


Console.WriteLine("Before calling SquareByReference, "

& "number2 is {0}", number2)

53

SquareByReference(number2) ' passes number2 by

reference

Console.WriteLine("After returning from " & _

"SquareByReference, number2 is {0}" & vbCrLf,

number2)


Console.WriteLine("Before calling SquareByReference "

& "using parentheses, number3 is {0}", number3)

SquareByReference(number3) ' passes number3 by value

Console.WriteLine("After returning from " &

"SquareByReference, number3 is {0}", number3)

End Sub

Sub SquareByValue(ByVal number As Integer)

Console.WriteLine("After entering SquareByValue, " &

"number is {0}", number)

number *= number

Console.WriteLine("Before exiting SquareByValue, " &

"number is {0}", number)

End Sub

Sub SquareByReference(ByRef number As Integer)

Console.WriteLine("After entering SquareByReference" &

", number is {0}", number)

number *= number

Console.WriteLine("Before exiting SquareByReference" &

", number is {0}", number)

End Sub

End Module

'Pass Integer by value to a function

Public Class m129


Dim myInteger As Integer = 5

TestByVal(myInteger)

Console.WriteLine(myInteger)

End Sub

Private Shared Sub TestByVal(ByVal int As Integer)

int = int * 2

End Sub

54

End Class

'Use named parameters

Option Strict On

Public Class Person

Private firstName As String

Private middleName As String

Private lastName As String

Public Sub New(ByVal firstName As String, ByVal middleName

As String, ByVal lastName As String)

Me.firstName = firstName

Me.middleName = middleName

Me.lastName = lastName

End Sub

End Class

Public Module CallingFunctions

Public Sub Main()

Dim person2 As New Person("John", "J.", "Smith")

Dim person1 As New Person(firstName:="John",

lastName:="Smith", middleName:="J.")

End Sub

End Module

'Using ParamArray to create variable-length parameter lists.

Module m131

Sub Main()

AnyNumberArguments()

AnyNumberArguments(2, 3)

AnyNumberArguments(7, 8, 9, 10)

55

End Sub ' Main

Sub AnyNumberArguments(ByVal ParamArray array1 _

As Integer())

Dim i, total As Integer

total = 0

If array1.Length = 0 Then

Console.WriteLine(" received 0 arguments.")

Else

Console.Write("The total of ")

For i = 0 To array1.GetUpperBound(0)

Console.Write(array1(i) & " ")

total += array1(i)

Next

Console.WriteLine("is {0}.", total)

End If

End Sub

End Module

'Recursively generates factorial of number

Public Class m132


Dim value As Integer = 12

Dim i As Integer

For i = 0 To value

Console.WriteLine(i & "! = " & Factorial(i))

Next

End Sub

Shared Function Factorial(ByVal number As Long) As Long

If number <= 1 Then ' base case

Return 1

Else

Return number * Factorial(number - 1)

End If

56

End Function ' Factorial

End Class

'Demonstrating Fibonacci sequence recursively

Public Class m133


Dim number As Integer = 13

Console.WriteLine("Fibonacci Value is " &

Fibonacci(number))

End Sub

' calculate Fibonacci value recusively

Shared Function Fibonacci(ByVal number As Integer) As Long

' check for base cases

If number = 1 OrElse number = 0 Then

Return number

Else

Return Fibonacci(number - 1) + Fibonacci(number -

2)

End If

End Function ' Fibonacci

End Class

'Overloads function

Public Class m134


Console.WriteLine(Min(10.1, 10))

57

Console.WriteLine(Min("last", "first"))

Console.WriteLine(Min(#1/1/2000#, #3/4/2000#))

End Sub

Overloads Shared Function Min(ByVal dblA As Double, ByVal

dblB As Double) As Double

Min = IIf(dblA < dblB, dblA, dblB)

End Function

Overloads Shared Function Min(ByVal strA As String, ByVal

strB As String) As String

Min = IIf(strA < strB, strA, strB)

End Function

Overloads Shared Function Min(ByVal dteA As Date, ByVal

dteB As Date) As Date

Min = IIf(dteA < dteB, dteA, dteB)

End Function

End Class

'Using overloaded methods

Public Class m135


Console.WriteLine("The square of Integer 7 is " & _

Square(7) & vbCrLf & "The square of Double " & _

"7.5 is " & Square(7.5))

End Sub

Shared Function Square(ByVal value As Integer) As Integer

Return Convert.ToInt32(value ^ 2)

End Function ' Square

Shared Function Square(ByVal value As Double) As Double

Return value ^ 2

End Function ' Square

End Class

58

'Using overloaded methods to print arrays of different types

Module m136

Sub Main()

Dim integerArray As Integer() = {1, 2, 3, 4, 5, 6}

Dim doubleArray As Double() = {1.1, 2.2, 3.3, 4.4,

5.5, 6.6, 7.7}

Dim charArray As Char() = {"H"c, "E"c, "L"c, "L"c,

"O"c}

PrintArray(integerArray)

PrintArray(doubleArray)

PrintArray(charArray)

End Sub ' Main

Sub PrintArray(ByVal inputArray() As Integer)

For Each element As Integer In inputArray

Console.Write(element.ToString() & " ")

Next element

Console.WriteLine(vbCrLf)

End Sub

Sub PrintArray(ByVal inputArray() As Double)

For Each element As Double In inputArray


Next element


End Sub

Sub PrintArray(ByVal inputArray() As Char)

For Each element As Char In inputArray


Next element


End Sub

End Module

'Method Overloads with different number of parameters

59

Public Class m137


Dim Alerter As New MyMessageBox

Alerter.Alert("No Problems!")

Alerter.Alert("No Problems!", MsgBoxStyle.Exclamation)

End Sub

End Class

Public Class MyMessageBox

Public Sub Alert(ByVal Text As String)

MsgBox(Text)

End Sub

Public Sub Alert(ByVal Text As String, ByVal Icon As

MsgBoxStyle)

MsgBox(Text, Icon)

End Sub

End Class

'Inheritance and overloads

Public Class m138


Dim objBob As New Bob

objBob.Walk("Now I'm walking...")

End Sub

End Class

Public Class Person1

Public Sub Walk()

Console.WriteLine("Walking...")

End Sub

End Class

60

Class Bob

Inherits Person1

Public Overloads Sub Walk(ByVal Text As String)

Console.WriteLine(Text)

End Sub

End Class

'Class with a constructor to initialize its member field value

Module YourClassTest

Sub Main()

Dim obj1 As New YourClass("AAA")

Dim obj2 As New YourClass("BBB")

Console.WriteLine(obj1.YourName)


End Sub ' Main

End Module

Public Class YourClass

Private yourNameValue As String ' course name for this

YourClass

' constructor initializes course name with String supplied

as argument

Public Sub New(ByVal name As String)

YourName = name ' initialize yourNameValue via

property

End Sub ' New

' property YourName

Public Property YourName() As String

Get ' retrieve yourNameValue

Return yourNameValue

End Get

Set(ByVal value As String) ' set yourNameValue

yourNameValue = value ' store the course name in

the object

End Set

61

End Property ' YourName

Public Sub DisplayMessage()

Console.WriteLine("Welcome to " & YourName & "!")

End Sub ' DisplayMessage

End Class ' YourClass

'Class with a constructor to initialize its member field value

Module YourClassTest

Sub Main()

Dim obj1 As New YourClass("AAA")

Dim obj2 As New YourClass("BBB")



End Sub ' Main

End Module

Public Class YourClass


YourClass

' constructor initializes course name with String supplied

as argument

Public Sub New(ByVal name As String)

YourName = name ' initialize yourNameValue via

property

End Sub ' New

' property YourName




End Get



the object

End Set



62



End Class ' YourClass

'Define your own Time Class

Module m142

Sub Main()

Dim time As New CTime() ' call CTime constructor

Console.WriteLine("The initial universal times is: " &

_

time.ToUniversalString() & vbCrLf & _

"The initial standard time is: " & _

time.ToStandardString())

time.SetTime(13, 27, 6) ' set time with valid settings

Console.WriteLine("Universal time after setTime is: "

& _

time.ToUniversalString() & vbCrLf & _

"Standard time after setTime is: " & _


time.SetTime(99, 99, 99) ' set time with invalid

settings

Console.WriteLine("Universal time: " &

time.ToUniversalString() & _

vbCrLf & "Standard time: " &


End Sub

End Module

Class CTime

Inherits Object

Private mHour As Integer ' 0 - 23

Private mMinute As Integer ' 0 - 59

Private mSecond As Integer ' 0 - 59

63

Public Sub New()

SetTime(0, 0, 0)

End Sub ' New

Public Sub SetTime(ByVal hourValue As Integer, _

ByVal minuteValue As Integer, ByVal secondValue As

Integer)

If (hourValue >= 0 AndAlso hourValue < 24) Then

mHour = hourValue

Else

mHour = 0

End If

If (minuteValue >= 0 AndAlso minuteValue < 60) Then

mMinute = minuteValue

Else

mMinute = 0

End If

If (secondValue >= 0 AndAlso secondValue < 60) Then

mSecond = secondValue

Else

mSecond = 0

End If

End Sub ' SetTime

' convert String to universal-time format

Public Function ToUniversalString() As String

Return String.Format("{0}:{1:D2}:{2:D2}", _

mHour, mMinute, mSecond)

End Function ' ToUniversalString

' convert to String in standard-time format

Public Function ToStandardString() As String

Dim suffix As String = " PM"

Dim format As String = "{0}:{1:D2}:{2:D2}"

Dim standardHour As Integer

If mHour < 12 Then

suffix = " AM"

End If

If (mHour = 12 OrElse mHour = 0) Then

standardHour = 12

Else

standardHour = mHour Mod 12

End If

Return String.Format(format, standardHour, mMinute, _

64

mSecond) & suffix

End Function

End Class

'Class that contains instance variable and a property to get

and set its value

Module YourClassTest1

Sub Main()

Dim obj As New YourClass2

Console.WriteLine("Initial course name is: " &

obj.YourName & vbCrLf)

obj.YourName = "new Name"

obj.DisplayMessage()

End Sub ' Mains

End Module

Public Class YourClass2


YourClass

' property YourName




End Get



the object

End Set


' display a welcome message to the YourClass user




End Class

'Implement an interface

65

Class YourClass144

Implements IFormattable

Public Value As String

Public Overridable Overloads Function ToString(ByVal _

Format As String, ByVal Provider As IFormatProvider) _

As String Implements IFormattable.ToString

ToString = Value

End Function

Public Sub New(ByVal Value As String)

Me.Value = Value

End Sub

End Class

Module M144

Sub Main()

Dim A As New YourClass("Hello VB.Net World")

Dim S As New String("Hello")

End Sub

End Module

'One Class implements two interfaces

Option Strict On

Imports System

Interface Printable

Sub Read()

Sub Write(ByVal obj As Object)

Property Status() As Integer

66

End Interface 'Printable

Interface Zippable

Sub Zip()

Sub Unzip()

End Interface

Public Class Document

Implements Zippable, Printable

Public Sub New(ByVal s As String)

Console.WriteLine("Creating document with: {0}", s)

End Sub 'New

Public Sub Read() Implements Printable.Read

Console.WriteLine("Implementing the Read Method for

Printable")

End Sub 'Read

Public Sub Write(ByVal o As Object) Implements

Printable.Write

Console.WriteLine( _

"Implementing the Write Method for Printable")

End Sub 'Write

Public Property Status() As Integer Implements

Printable.Status

Get

Return myStatus

End Get

Set(ByVal Value As Integer)

myStatus = Value

End Set

End Property

Public Sub Zip() Implements Zippable.Zip

Console.WriteLine("Implementing Zip")

End Sub

Public Sub Unzip() Implements Zippable.Unzip

Console.WriteLine("Implementing Unzip")

End Sub

Private myStatus As Integer = 0

End Class

Class m145

Shared Sub Main()

Dim doc As New Document("Test Document")

doc.Status = -1

doc.Read()

67

doc.Zip()

Console.WriteLine("Document Status: {0}", doc.Status)

End Sub 'Main

End Class

'Inheritance And Interfaces

Imports System

Imports System.Collections

Public Interface Printable1

ReadOnly Property Print() As Integer

End Interface

Public Class Money

Implements Printable1

Protected mTransactions As New ArrayList()

ReadOnly Property Print() As Integer Implements

Printable1.Print

Get

Return mTransactions.Count

End Get

End Property

Public Overridable ReadOnly Property Balance() As Double

Get

Dim result As Double = 0.0

Dim i As Integer

For i = 0 To mTransactions.Count - 1

result += CDbl(mTransactions(i))

Next

Return result

End Get

End Property

Public Sub Add(ByVal amount As Double)

mTransactions.Add(amount)

End Sub

Public Sub Subtract(ByVal amount As Double)

mTransactions.Add(-amount)

End Sub

68

End Class

Public Class MyMoney

Inherits Money

Public Overrides ReadOnly Property Balance() As Double

Get

Return MyBase.Balance - Print * 2

End Get

End Property

End Class

Module m146

Sub Main()

Dim acc1 As New Money()

acc1.Add(200)

acc1.Subtract(40)

acc1.Add(30)

Console.Write("count: {0}, ", acc1.Print)

Console.WriteLine("balance: {0}", acc1.Balance)

Dim acc2 As New MyMoney()

acc2.Add(200)

acc2.Subtract(40)

acc2.Add(30)

Console.Write("count: {0}, ", acc2.Print)

Console.WriteLine("balance: {0}", acc2.Balance)

End Sub

End Module

'Reimplement interface

Class BaseClass

Implements IFormattable

Implements IComparable

Public Value As String

Public Overridable Overloads Function ToString(ByVal _


69

As String Implements IFormattable.ToString

ToString = Value

End Function

Public Overridable Overloads Function CompareTo(ByVal A _

As Object) As Integer Implements IComparable.CompareTo

If (Value = A.Value) Then

CompareTo = 0

ElseIf (Value < A.Value) Then

CompareTo = -1

Else

CompareTo = 1

End If

End Function


Me.Value = Value

End Sub

End Class

Class DerivedClass

Inherits BaseClass

Public Overrides Function ToString(ByVal _


As String

ToString = UCase(Value)

End Function


MyBase.New(Value)

End Sub

End Class

Module M147

Sub Main()

Dim A As New BaseClass("Hello")

Dim B As New DerivedClass("Hi")

Console.WriteLine(A)

Console.WriteLine(B)

Console.WriteLine(A.CompareTo(B))

End Sub

End Module

70

'Public Sub aMethod() Implements Interface1.Method,

Interface2.Method

Public Interface I1

Sub Draw()

End Interface

Public Interface I2

Sub Draw()

End Interface

Public Class Class1

Implements I1, I2

Public Sub foo() Implements I1.Draw, I2.Draw

End Sub

End Class

'Two classes implement one interface

Public Class m149


Dim rect As New Rectangle()

Dim trap As New Trapezoid()

rect.Draw()

trap.Draw()

End Sub

End Class

Public Interface IShape

Function Draw() As String

End Interface

Public Class Rectangle

Implements IShape

Public Function Draw() As String Implements IShape.Draw

Return "Drawing Rectangle"

End Function

End Class

Public Class Trapezoid

Implements IShape

Public Function Draw() As String Implements IShape.Draw

71

Return "Drawing Trapezoid"

End Function

End Class

'Shadow member variable in base class

Module M150

Class BaseClass

Public Name As String

Public Amount As Integer

Public Message As String

Public Sub New(ByVal Name As String, ByVal Amount As

Integer, ByVal Message As String)

Me.Name = Name

Me.Amount = Amount

Me.Message = Message

End Sub

Public Sub ShowBaseMembers()


Console.WriteLine("Amount: " & Amount)

Console.WriteLine("Message: " & Message)

End Sub

End Class

Class DerivedClass

Inherits BaseClass

' Public Amount As Double

Public Shadows Message As String

Public Sub ShowDerivedMembers()


Console.WriteLine("Amount: " & Amount)

Console.WriteLine("Message: " & Message)

End Sub

Public Sub New(ByVal Name As String, ByVal Amount As

Integer, ByVal Message As String)

MyBase.New(Name, Amount, Message)

End Sub

72

End Class

Sub Main()

End Sub

End Module

'Method with parameter

Option Strict On

Imports System

Public Class TestClass

Sub SomeMethod(ByVal firstParam As Integer, ByVal

secondParam As Single)

Console.WriteLine("received: {0}, {1}", firstParam,

secondParam)

End Sub

End Class

Module M151

Sub Main()

Dim howManyPeople As Integer = 5

Dim pi As Single = 3.14F

Dim tc As New TestClass()

tc.SomeMethod(howManyPeople, pi)

End Sub

End Module

'Simple Inheritance

Public Class m152

73


Dim objJohn As New John1

objJohn.Walk()

End Sub

End Class

Public Class ok

Public Sub Walk()


End Sub

End Class

Class John1

Inherits ok

End Class

'Multilevel inheritance

Class Person11


Public Age As Integer

Public Sub New(ByVal Name As String, ByVal Age As Integer)

Me.Name = Name

Me.Age = Age

End Sub

End Class

Class Player

Inherits Person11

Public Sport As String

Public Team As String

Public Sub New(ByVal Name As String, ByVal Age As Integer,

_

ByVal Sport As String, ByVal Team As String)

MyBase.New(Name, Age)

Me.Team = Team

Me.Sport = Sport

End Sub

End Class

Class BasketPlayer

74

Inherits Player

Public PointsPerGame As Double

Public Rebounds As Double

Public Sub New(ByVal Name As String, ByVal Age As Integer,

_

ByVal Sport As String, ByVal Team As String, ByVal Points

As Double, ByVal Rebounds As Double)

MyBase.New(Name, Age, Sport, Team)

Me.PointsPerGame = Points

Me.Rebounds = Rebounds

End Sub

Public Sub Show()

Console.WriteLine("Player: " & Name)

Console.WriteLine("Age: " & Age)

Console.WriteLine("Sport: " & Sport)

Console.WriteLine("Team: " & Team)

Console.WriteLine("Points: " & PointsPerGame)

Console.WriteLine("Rebounds: " & Rebounds)

End Sub

End Class

Module M153

Sub Main()

Dim K As New BasketPlayer("AA", 12, "Basketball",

"Team", 25.5, 6.3)

K.Show()

End Sub

End Module

'Polymorphic Behaviour

Class ID

Public Number As String

Public Sub New(ByVal Number As String)

Me.Number = Number

End Sub

Public Overridable Sub Dial()

75

Console.WriteLine("Dialing: " & Number)

End Sub

End Class

Class Phone

Inherits ID


MyBase.New(Number)

End Sub

Public Overrides Sub Dial()

Console.WriteLine("Beep, touch-tone phone calling: " &

Number)

End Sub

End Class

Class CreditCardID

Inherits ID


MyBase.New(Number)

End Sub

Public Overrides Sub Dial()

Console.WriteLine("Rotary dialing: " & Number)

End Sub

End Class

Module M154

Sub Main()

Dim card As New CreditCardID("555-1212")

Dim phone As New Phone("800-555-1212")

Dim PolyID As ID

Console.WriteLine("Using standard objects")

card.Dial()

phone.Dial()

Console.WriteLine("Using polymorphic phone")

PolyID = card

PolyID.Dial()

PolyID = phone

PolyID.Dial()

End Sub

End Module

76

'Late binding

Public Class m155


Dim objHorse As Object

Dim objPuma As Object

objHorse = New Horse

objPuma = New Puma

Try

objHorse.Walk()

Catch

Console.WriteLine("Sorry, no Walk method available

in objHorse.")

End Try

Try

objPuma.Walk()

Catch

Console.WriteLine("Sorry, no Walk method available

in objPuma.")

End Try

End Sub

End Class

Public Class Horse

Public Sub Walk()


End Sub

End Class

Public Class Puma

Public Sub Run()

Console.WriteLine("Running...")

End Sub

End Class

'Inherits' must be first line. There can be only one

77

Public Class P

Inherits System.Object


Public Birthday As Date

End Class

Public Class Student

Inherits P

Public Sub New(ByVal StudentName As String, ByVal

BirthDate As Date)

MyBase.Name = StudentName

MyBase.Birthday = BirthDate

End Sub

Public StudentID


Return (Me.Name)

End Function

End Class

'Call Shared method

Option Strict On

Imports System

Class YourCl

Private Shared instances As Integer = 0

Private weight As Integer

Private name As String

Public Sub New(ByVal name As String, ByVal weight As

Integer)

instances += 1

Me.name = name

Me.weight = weight

End Sub

Public Shared Sub SharedMerthod()

Console.WriteLine("{0} cats adopted", instances)

End Sub

Public Sub TellWeight()

Console.WriteLine("{0} is {1} pounds", name, weight)

End Sub

78

End Class

Module M157

Sub Main()

YourCl.SharedMerthod()

Dim obj As New YourCl("A", 5)

obj.TellWeight()


Dim obj2 As New YourCl("B", 7)

obj2.TellWeight()



End Sub

End Module

'Shared field

Public Class m158


Dim Counter1 As New Counter

Dim Counter2 As New Counter

Console.WriteLine("Total count = " & Counter1.Count())








End Sub

End Class

Public Class Counter

Shared Data As Integer = 0

Public Function Count() As Integer

Data += 1

Return Data

End Function

End Class

79

'Class with Private fields and Public method

Imports System

Public Class Time

' Private variables

Private Year As Integer

Private Month As Integer

Private Hour As Integer

Private Minute As Integer

Private Second As Integer

' Public methods

Public Sub DisplayCurrentTime()

Console.WriteLine("stub for DisplayCurrentTime")

End Sub 'DisplayCurrentTime

End Class 'Time

Module M159

Sub Main()

Dim timeObject As New Time()

timeObject.DisplayCurrentTime()

End Sub

End Module

'Define delegate

Public Class m160

Private Delegate Function NumEmployeesDelegate() As

Integer

Private Delegate Function GetNameDelegate() As String


Dim emp As New Employee()

Dim show_name As GetNameDelegate

show_name = AddressOf emp.ToString

Console.WriteLine(show_name())

80

End Sub

End Class

Public Class Employee

Public Shared Function GetNumEmployees() As Integer

Return 13

End Function


Return "Employee"

End Function

End Class

'Delegate Function

Module M161

Delegate Function Numbers(ByVal A As Double, ByVal B As

Double) As Double

Function SubtractNumbers(ByVal A As Double, ByVal B As

Double) As Double

SubtractNumbers = A - B

End Function

Function AddNumbers(ByVal A As Double, ByVal B As Double)

As Double

AddNumbers = A + B

End Function

Sub Main()

Dim DoNumbers As New Numbers(AddressOf

SubtractNumbers)

Console.WriteLine(DoNumbers.Invoke(100, 50))

DoNumbers = AddressOf AddNumbers

Console.WriteLine(DoNumbers.Invoke(100, 50))

End Sub

End Module

81

'Uses delegates to sort random numbers (ascending or

descending)

Public Class m162

Private Shared Function SortAscending(ByVal element1 As

Integer, _

ByVal element2 As Integer) As Boolean

Return element1 > element2

End Function ' SortAscending

Private Shared Function SortDescending(ByVal element1 As

Integer, _


Return element1 < element2

End Function ' SortDescending


Dim mBubbleSort As New BubbleSort()

Dim mElementArray As Integer() = New Integer(9) {}

Dim randomNumber As Random = New Random()

Dim i As Integer

' create String with 10 random numbers

For i = 0 To mElementArray.GetUpperBound(0)

mElementArray(i) = randomNumber.Next(100)

Console.WriteLine(mElementArray(i))

Next

mBubbleSort.SortArray(mElementArray, AddressOf

SortAscending)


Console.Write(mElementArray(i) & " ")

Next

Console.WriteLine()

mBubbleSort.SortArray(mElementArray, AddressOf

SortDescending)


Console.Write(mElementArray(i) & " ")

Next

End Sub

82

End Class

Public Class BubbleSort

Public Delegate Function Comparator( _

ByVal element1 As Integer, _


Public Sub SortArray(ByVal array As Integer(), _

ByVal Compare As Comparator)

Dim i, pass As Integer

For pass = 0 To array.GetUpperBound(0)

For i = 0 To array.GetUpperBound(0) - 1

If Compare(array(i), array(i + 1)) Then

Swap(array(i), array(i + 1))

End If

Next ' inner loop

Next ' outer loop

End Sub ' SortArray

Private Sub Swap(ByRef firstElement As Integer, _

ByRef secondElement As Integer)

Dim hold As Integer

hold = firstElement

firstElement = secondElement

secondElement = hold

End Sub ' Swap

End Class

'Multiple Delegates

Module M163

Delegate Sub NotifyInfo()

Dim ListOfDelegates(3) As NotifyInfo

Sub Testing()

Console.WriteLine("AAA")

End Sub

Sub Coding()

83

Console.WriteLine("BBB")

End Sub

Sub Meeting()

Console.WriteLine("CCC")

End Sub

Sub Main()

ListOfDelegates(0) = New NotifyInfo(AddressOf Coding)

ListOfDelegates(1) = New NotifyInfo(AddressOf Testing)

ListOfDelegates(2) = New NotifyInfo(AddressOf Meeting)

Dim NotifyAll As New NotifyInfo(AddressOf Coding)

NotifyAll = NotifyInfo.Combine(ListOfDelegates)

NotifyAll.Invoke()

End Sub

End Module

'Friend members are available to any object in the same

assembly (Friend is referred to as internal in C#)

Public Class SomeClassInMyAssembly

Friend vFriend As Integer

End Class

'Class with constructor

Option Strict On

Imports System

Public Class Time1

' Private variables

84



Private mDate As Integer



Private Second As Integer

' Public methods


System.Console.WriteLine("{0}/{1}/{2} {3}:{4}:{5}",

Month, mDate, Year, Hour, Minute, Second)


' Constructor

Public Sub New(ByVal theYear As Integer, ByVal theMonth As

Integer, _

ByVal theDate As Integer, ByVal theHour As

Integer, _

ByVal theMinute As Integer, ByVal theSecond

As Integer)

Year = theYear

Month = theMonth

mDate = theDate

Hour = theHour

Minute = theMinute

Second = theSecond

End Sub

End Class 'Time

Module Module166

Sub Main()

Dim timeObject As New Time1(2005, 3, 25, 9, 35, 20)


End Sub

End Module

'Empty constructor

Imports System

Module m167

85

Sub Main()

Dim p1 As New Point()

Dim p2 As New Point(100, 100)

Console.WriteLine(p1)


End Sub

End Module

Class Point

Private X As Integer

Private Y As Integer

Sub New()

End Sub

Sub New(ByVal x As Integer, ByVal y As Integer)

Me.X = x

Me.Y = y

End Sub


Return ("(" & X & "," & Y & ")")

End Function

End Class

'Default constructor

Imports System

Module m168

Sub Main()

Dim p1 As New Point1()

Dim p2 As New Point1()

p2.Y = 100

p2.X = 100



End Sub

End Module

Class Point1

Public X As Integer

Public Y As Integer

86


Return ("(" & X & "," & Y & ")")

End Function

End Class

'Copy constructor

Option Strict On

Imports System

Public Class Time2

' Private variables



Private mDate As Integer



Private Second As Integer = 30

' Public methods


System.Console.WriteLine("{0}/{1}/{2} {3}:{4}:{5}", _

Month, mDate, Year, Hour, Minute, Second)


Public Sub New( _

ByVal theYear As Integer, _

ByVal theMonth As Integer, _

ByVal theDate As Integer, _

ByVal theHour As Integer, _

ByVal theMinute As Integer)

Year = theYear

Month = theMonth

mDate = theDate

Hour = theHour

Minute = theMinute

End Sub

Public Sub New(ByVal existingObject As Time2)

Year = existingObject.Year

Month = existingObject.Month

mDate = existingObject.mDate

Hour = existingObject.Hour

Minute = existingObject.Minute

Second = existingObject.Second

87

End Sub

End Class 'Time

Module Module169

Sub Main()

Dim timeObject As New Time2(2005, 3, 25, 9, 35)

Dim t2 As New Time2(timeObject)


t2.DisplayCurrentTime()

End Sub

End Module

'Constructors in three levels

Class A

Public Sub New()

Console.WriteLine("In class A constructor")

End Sub

End Class

Class B

Inherits A

Public Sub New()

Console.WriteLine("In class B constructor")

End Sub

End Class

Class C

Inherits B

Public Sub New()

Console.WriteLine("In class C constructor")

End Sub

End Class

Module Module170

Sub Main()

Dim objSample As New C()

End Sub

End Module

88

'Overloaded constructors

Module m171

Sub Main()

' use overloaded constructors

Dim time1 As New MyTime()

Dim time2 As New MyTime(2)

Dim time3 As New MyTime(21, 34)

Dim time4 As New MyTime(12, 25, 42)

Dim time5 As New MyTime(27, 74, 99)

Dim time6 As New MyTime(time4) ' use time4 as initial

value

Console.WriteLine(time1.ToUniversalString())






End Sub ' Main

End Module

Class MyTime

Inherits Object

Private mHour As Integer ' 0 - 23

Private mMinute As Integer ' 0 - 59

Private mSecond As Integer ' 0 - 59

Public Sub New()

SetTime()

End Sub ' New

Public Sub New(ByVal hourValue As Integer)

SetTime(hourValue)

End Sub ' New

89

Public Sub New(ByVal hourValue As Integer, _

ByVal minuteValue As Integer)

SetTime(hourValue, minuteValue)

End Sub ' New

Public Sub New(ByVal hourValue As Integer, _

ByVal minuteValue As Integer, ByVal secondValue As

Integer)

SetTime(hourValue, minuteValue, secondValue)

End Sub ' New

Public Sub New(ByVal timeValue As MyTime)

SetTime(timeValue.mHour, timeValue.mMinute,

timeValue.mSecond)

End Sub ' New

Public Sub SetTime(Optional ByVal hourValue As Integer =

0, _

Optional ByVal minuteValue As Integer = 0, _

Optional ByVal secondValue As Integer = 0)

If (hourValue >= 0 AndAlso hourValue < 24) Then

mHour = hourValue

Else

mHour = 0

End If

If (minuteValue >= 0 AndAlso minuteValue < 60) Then

mMinute = minuteValue

Else

mMinute = 0

End If

If (secondValue >= 0 AndAlso secondValue < 60) Then

mSecond = secondValue

Else

mSecond = 0

End If

End Sub ' SetTime

Public Function ToUniversalString() As String

Return String.Format("{0}:{1:D2}:{2:D2}", _

mHour, mMinute, mSecond)

End Function ' ToUniversalString

End Class

90

'Call member method in constructor

Option Strict On

Public Class Counters

Dim ctr As Integer

Public Sub New()

For ctr = 1 To 20

DoSomething()

Next

End Sub

Public Sub DoSomething()

Console.WriteLine(Me.ctr)

End Sub

End Class

Public Module modMain

Public Sub Main()

Dim obj As New Counters()

End Sub

End Module

'Inheriting Constructors

Public Class Test1


Dim objJohn As New John("Walking...")

objJohn.Walk()

End Sub

End Class

Public Class Person5

Private Text As String

Public Sub New(ByVal Message As String)

Text = Message

91

End Sub

Public Sub Walk()


End Sub

End Class

Class John

Inherits Person5


MyBase.New(Message)

End Sub

End Class

'Shared Constructor


Private Shared ID As Integer = 10

Public Shared ReadOnly Property CurrentID() As Integer

Get

Return ID

End Get

End Property

Public Shared Function GetID() As Integer

ID += 1

Return ID

End Function

Shared Sub New()

Console.WriteLine("Before init: " & ID)

ID = 100

Console.WriteLine("After init: " & ID)

End Sub

End Class

Module m175

Sub Main()

Dim CountValue As Integer

For CountValue = 1 To 10

Console.WriteLine(YourClass175.GetID())

Next

End Sub

92

End Module

'Constructor with Optional parameter

Public Class Point2

Private MX As Integer

Private MY As Integer

Public Sub New(Optional ByVal X As Integer = 0, Optional

ByVal Y As Integer = 0)

MX = X

MY = Y

End Sub


Return "(" & MX & "," & MY & ")"

End Function

End Class

Module OptionalPoint

Sub Main()

Dim P1 As New Point2()

Console.WriteLine(P1.ToString())

Dim P2 As New Point2(1, 1)


Dim P3 As New Point2(, 1)


Dim P4 As New Point2(9, )


End Sub

End Module

'Constructor Chain

93


Public Address As String = "Default"

Public City As String = "Default"

Sub New()

MyBase.New()

Console.WriteLine("YourClass Created")

End Sub

Sub New(ByVal A As String, ByVal C As String)

Me.New()

Address = A

City = C

Console.WriteLine("YourClass.Address and Set")

End Sub

End Class

Module m177

Sub Main()

Dim SL As New YourClass177("123 First Street",

"Somewhere")

End Sub

End Module

'constructor inheriting

Public Class Address

Private MyState As String = "DEFAULT"

Sub New()

MyBase.New()

Console.WriteLine("Address Created")

End Sub

Public Property State() As String

Get

Return MyState

End Get

Set(ByVal Value As String)

MyState = Value

94

End Set

End Property

End Class

Public Class MyAddress

Inherits Address

Private MyAddress As String

Sub New()

MyBase.New()

Console.WriteLine("MyAddress Created")

End Sub

Public Property Address() As String

Get

Return MyAddress

End Get

Set(ByVal Value As String)

MyAddress = Value

End Set

End Property

End Class

Module Test178

Sub Main()

Dim SL As New MyAddress()

SL.State = "CANADA"

SL.Address = "123"

End Sub

End Module

'Destructor in three levels

Class A5

Public Sub New()

Console.WriteLine("In class A constructor")

End Sub

Protected Overrides Sub Finalize()

Console.WriteLine("In class A destructor")

MyBase.Finalize()

End Sub

95

End Class

Class B5

Inherits A5

Public Sub New()

Console.WriteLine("In class B constructor")

End Sub


Console.WriteLine("In class B destructor")

MyBase.Finalize()

End Sub

End Class

Class C5

Inherits B5

Public Sub New()

Console.WriteLine("In class C constructor")

End Sub


Console.WriteLine("In class C destructor")

MyBase.Finalize()

End Sub

End Class

Module Module179

Sub Main()

Dim objSample As New C5()

End Sub

End Module

'Inherit destructor

Class Base

Public Sub New()

Console.WriteLine("The Base Class Constructor is

Running")

End Sub


Console.WriteLine("The Base Class Destructor is

96

Running")

MyBase.Finalize()

End Sub

End Class

Class Derived

Inherits Base

Public Sub New()

Console.WriteLine("The Derived Class Constructor is

Running")

End Sub


Console.WriteLine("The Derived Class Destructor is

Running")

MyBase.Finalize()

End Sub

End Class

Module Module180

Sub Main()

Dim Sample As New Derived()

End Sub

End Module

'Call constroctor from base class

Option Strict On

Imports System

Public Class Rectangle11

Public Sub New(ByVal top As Integer, ByVal left As

Integer)

Me.top = top

Me.left = left

End Sub

Public Sub DrawRectangle()

Console.WriteLine("Drawing Rectangle at {0}, {1}",

top, left)

End Sub

Private top As Integer

Private left As Integer

97

End Class

Public Class NamedRectangle

Inherits Rectangle11


Integer, ByVal n As String)

MyBase.New(top, left)

RectName = n

End Sub 'New

Public Shadows Sub DrawRectangle()

MyBase.DrawRectangle()

Console.WriteLine("Writing string to the listbox:

{0}", RectName)

End Sub

Private RectName As String

End Class

Module Module181

Sub Main()

Dim w As New Rectangle11(5, 10)

w.DrawRectangle()

Dim lb As New NamedRectangle(20, 30, "Hello")

lb.DrawRectangle()

End Sub

End Module

'Call method with MyBase

Option Strict On

Imports System

Public Class Control


Integer)

Me.top = top

Me.left = left

End Sub

Public Overridable Sub DrawControl()

Console.WriteLine("Control: drawing Control at {0},

98

{1}", top, left)

End Sub

Protected top As Integer

Protected left As Integer

End Class

Public Class Label

Inherits Control




text = n

End Sub

Public Overrides Sub DrawControl()

MyBase.DrawControl()


{0}", text)

End Sub

Private text As String

End Class

Public Class Button

Inherits Control


Integer)


End Sub 'New


Console.WriteLine("Drawing a button at {0}, {1}" +

ControlChars.Lf, top, Left)

End Sub

End Class


Shared Sub Main()

Dim win As New Control(1, 2)

Dim lb As New Label(3, 4, "test")

Dim b As New Button(5, 6)

win.DrawControl()

lb.DrawControl()

b.DrawControl()

Dim winArray(3) As Control

99

winArray(0) = New Control(1, 2)

winArray(1) = New Label(3, 4, "AAA")

winArray(2) = New Button(5, 6)

Dim i As Integer

For i = 0 To 2

winArray(i).DrawControl()

Next i

End Sub

End Class

'Override ToString method

Option Strict On

Imports System

Public Class Dog

Private weight As Integer

Public Sub New(ByVal weight As Integer)

Me.weight = weight

End Sub


Return weight.ToString()

End Function

End Class


Shared Sub Main()

Dim i As Integer = 5

Console.WriteLine(i.ToString())

Dim milo As New Dog(62)

Console.WriteLine(milo.ToString())

End Sub

End Class

'Assign string value to an Object variable

100

Public Class Test184


Dim objMyModemSpeed As Object

objMyModemSpeed = "28.8"

Console.WriteLine(objMyModemSpeed)

Console.WriteLine(objMyModemSpeed * 1000 / 8)

objMyModemSpeed = Nothing

End Sub

End Class

'Create an object and call its method.

Module YourClassTest185

Sub Main()

Dim obj As New YourClass11()

obj.DisplayMessage()

End Sub

End Module



Console.WriteLine("Welcome!")

End Sub

End Class

'Sort objects in an array




101

Dim people(4) As Employee1

people(0) = New Employee1("R", "S")

people(1) = New Employee1("S", "A")

people(2) = New Employee1("T", "P")

people(3) = New Employee1("H", "S")

people(4) = New Employee1("E", "C")

' Sort.

Array.Sort(people)

For i As Integer = 0 To people.GetUpperBound(0)

Console.WriteLine(people(i).ToString())

Next i

End Sub

End Class



Public FirstName As String

Public LastName As String

Public Sub New(ByVal first_name As String, ByVal last_name

As String)

FirstName = first_name

LastName = last_name

End Sub


Return LastName & ", " & FirstName

End Function

Public Function CompareTo(ByVal obj As Object) As Integer

_

Implements System.IComparable.CompareTo

Dim other_Employee As Employee = DirectCast(obj,

Employee)

Return String.Compare(Me.ToString,

other_Employee.ToString)

End Function

End Class

'Define and use a Property

Option Strict On

102

Imports System

Public Class Cat

Private mWeight As Integer

Public Sub New(ByVal weight As Integer)

mWeight = weight

End Sub

Public Property Weight() As Integer

Get

Return mWeight

End Get


mWeight = Value

End Set

End Property


Return mWeight.ToString()

End Function

End Class

Module Module187

Sub Main()

Dim theVariable As New Cat(5)

Console.WriteLine("In Run. theVariable: {0}",

theVariable)

Doubler(theVariable)

Console.WriteLine("Back in Run. theVariable: {0}",

theVariable)

End Sub

Public Sub Doubler(ByVal param As Cat)

Console.WriteLine("In Method1. Received param: {0}",

param)

param.Weight = param.Weight * 2

Console.WriteLine("Updated param. Returning new value:

{0}", param)

End Sub

End Module

103

'Use MustInherit to define abstract class

Public MustInherit Class Printable2

Public PageData As String

Public MustOverride Sub ShowPage()


PageData = Message

End Sub

End Class

Public Class Word

Inherits Printable2

Public Overrides Sub ShowPage()

Console.WriteLine("word: " & PageData)

End Sub


MyBase.New(Message)

End Sub

End Class

Public Class Text

Inherits Printable2

Public Overrides Sub ShowPage()

Console.WriteLine("Test: " & PageData)

End Sub


MyBase.New(Message)

End Sub

End Class

Module Module188

Sub Main()

Dim WebPage As Word = New Word("word page")

104

Dim MobilePage As Text = New Text("text file")

WebPage.ShowPage()

Console.WriteLine()

MobilePage.ShowPage()

End Sub

End Module

'MustInherit class

Option Strict On

Imports System

Public MustInherit Class Control1


Integer)

Me.top = top

Me.left = left

End Sub

Public MustOverride Sub DrawControl()



End Class

Public Class Label1

Inherits Control1


Integer, ByVal contents As String)


listBoxContents = contents

End Sub



{0}", listBoxContents)

End Sub

Private listBoxContents As String

End Class

105

Public Class Button1

Inherits Control1


Integer)


End Sub



ControlChars.Lf, top, left)

End Sub

End Class


Shared Sub Main()

Dim winArray(3) As Control1

winArray(0) = New Label1(1, 2, "A")

winArray(1) = New Label1(3, 4, "B")

winArray(2) = New Button1(5, 6)

Dim i As Integer

For i = 0 To 2


Next i

End Sub 'Main

End Class 'Tester

'MustOverride method

Option Strict On

Imports System

Public MustInherit Class Control2


Integer)

Me.top = top

Me.left = left

End Sub

Public MustOverride Sub DrawControl()

106



End Class

Public Class Label2

Inherits Control2


Integer, ByVal contents As String)


listBoxContents = contents

End Sub



{0}", listBoxContents)

End Sub

Private listBoxContents As String

End Class


Inherits Control2


Integer)


End Sub



ControlChars.Lf, top, left)

End Sub

End Class


Shared Sub Main()


winArray(0) = New Label2(1, 2, "A")

winArray(1) = New Label2(3, 4, "B")


Dim i As Integer

For i = 0 To 2


Next i

End Sub 'Main

End Class 'Tester

107

'NotOverridable

Public Class Base1

Public Overridable Function greet() As String

Return "Greeting from the Base!"

End Function

End Class

Public Class Derived11

Inherits Base1

Public Overrides Function greet() As String

Return "middle greet"

End Function

End Class

Public Class Derived21

Inherits Derived11

Public NotOverridable Overrides Function greet() As String

'End Function

Return 0

End Function

End Class

Public Class bottom11

Inherits Derived21

End Class

'Overridable Overrides methods

Option Strict On

Imports System

Public Class Control3


Integer)

Me.top = top

Me.left = left

End Sub

Public Overridable Sub DrawControl()

Console.WriteLine("Control: drawing Control at {0},

{1}", top, left)

108

End Sub



End Class

Public Class Label3

Inherits Control3




text = n

End Sub


MyBase.DrawControl()


{0}", text)

End Sub

Private text As String

End Class


Inherits Control3


Integer)


End Sub 'New



ControlChars.Lf, top, Left)

End Sub

End Class

Public Class m192

Shared Sub Main()

Dim win As New Control3(1, 2)

Dim lb As New Label3(3, 4, "test")

Dim b As New Button3(5, 6)

win.DrawControl()

lb.DrawControl()

b.DrawControl()


winArray(0) = New Control3(1, 2)

109

winArray(1) = New Label3(3, 4, "AAA")


Dim i As Integer

For i = 0 To 2


Next i

End Sub

End Class

'Structure

Structure Money1

Private centsAmount As Integer

Public Sub New(ByVal amount As Double)

Me.centsAmount = CInt(amount * 100)

End Sub

End Structure

Module MyModule

Sub Main()

' Dim freebie As Money1

Dim carPrice As Money1 = New Money1(3.95)

End Sub

End Module

'Define and use Structure

Structure CheckRecord

Dim intCheckNumber As Integer

Dim dteCheckDate As Date

Dim sngCheckAmount As Single

Dim strCheckPaidTo As String

110

End Structure



Dim udtCheck As CheckRecord

'Add data to the structure.

udtCheck.intCheckNumber = 275

udtCheck.dteCheckDate = #9/12/2001#

udtCheck.sngCheckAmount = 104.25

udtCheck.strCheckPaidTo = "Gas Co."

Console.WriteLine("CHECK INFORMATION")

Console.WriteLine("Number: " &

udtCheck.intCheckNumber)

Console.WriteLine("Date: " & udtCheck.dteCheckDate)

Console.WriteLine("Amount: " &

udtCheck.sngCheckAmount)

Console.WriteLine("Paid To: " &

udtCheck.strCheckPaidTo)

End Sub

End Class

'By value or by reference

Option Strict On

Public Class YourClas


Public GPA As Double

End Class

Public Structure YourStructure


Public GPA As Double

End Structure



Dim valueByRef As New YourClas()

Dim valueByValue As New YourStructure()

111

valueByRef.Name = "Jill"

valueByRef.GPA = 92.3

valueByValue.Name = "Jill"

valueByValue.GPA = 92.3

Dim ref2 As YourClas = valueByRef

Dim value2 As YourStructure = valueByValue

ref2.GPA += 2

value2.GPA += 2

Console.WriteLine("{0}'s GPA is: {1}",

valueByRef.Name, valueByRef.GPA)

Console.WriteLine("{0}'s GPA is: {1}",

valueByValue.Name, valueByValue.GPA)

End Sub

End Class

'Use Structure as Function parameter

Public Structure CustomerBalance

Dim decBalSavings As Decimal

Dim decBalChecking As Decimal

End Structure



Dim udtBalance As CustomerBalance

udtBalance = GetCustomerBalance(1)

Console.WriteLine(udtBalance.decBalChecking)

Console.WriteLine(udtBalance.decBalSavings)

End Sub

Shared Function GetCustomerBalance(ByVal intCustomerID As

Integer) As CustomerBalance

Dim udtBalance As CustomerBalance

udtBalance.decBalChecking = CDec(1000 + 4000 * Rnd())

udtBalance.decBalSavings = CDec(1000 + 15000 * Rnd())

Return udtBalance

112

End Function

End Class

'Class Vs Structure in ByValue and ByRef

Imports System

Public Enum Country

US = 1

CA = 2

End Enum

Public Class AClass


Public Status As Country

End Class

Public Structure AStruct


Public Status As Country

End Structure

Public Module Test197

Public Sub ChangeName_Obj_ByVal(ByVal details As AClass,

ByVal NewName As String)

details.Name = NewName

End Sub

Public Sub ChangeName_Obj_ByRef(ByRef details As AClass,

ByVal NewName As String)


End Sub

Public Sub ChangeName_Struct_ByVal(ByVal details As

AStruct, ByVal NewName As String)


End Sub

Public Sub ChangeName_Struct_ByRef(ByRef details As

AStruct, ByVal NewName As String)


End Sub

113

Sub Main()

Dim classInstance As AClass = New AClass()

Dim structInstance As AStruct = New AStruct()

classInstance.Name = "A"

classInstance.Status = Country.CA

structInstance.Name = "B"

structInstance.Status = Country.CA

Console.WriteLine("{0}, {1}", classInstance.Name,

classInstance.Status)

Console.WriteLine("{0}, {1}", structInstance.Name,

structInstance.Status)

Console.WriteLine()

ChangeName_Obj_ByVal(classInstance, "AAAA")

ChangeName_Struct_ByVal(structInstance, "BBBB")

Console.WriteLine("{0},{1}", classInstance.Name,


Console.WriteLine("{0},{1}", structInstance.Name,


Console.WriteLine()

ChangeName_Obj_ByRef(classInstance, "AAAA")

ChangeName_Struct_ByRef(structInstance, "BBBB")

Console.WriteLine("{0}, {1}", classInstance.Name,


Console.WriteLine("{0}, {1}", structInstance.Name,


End Sub

End Module

'Array of Structure

Structure Employee5

Dim strName As String

Dim intSalary As Integer

End Structure



Dim aryEmployees(15) As Employee5

Dim intCounter As Integer

114

aryEmployees(0).strName = "J"

aryEmployees(0).intSalary = 3

aryEmployees(1).strName = "B"


'Set other array elements here.

aryEmployees(15).strName = "P"


'Show the elements of the array.

For intCounter = 0 To 15

Console.WriteLine("Array element: " & intCounter &

vbCrLf & _

"Name: " & aryEmployees(intCounter).strName

& vbCrLf & _

"Salary: " &

aryEmployees(intCounter).intSalary)

Next intCounter

End Sub

End Class

'Try Catch Exception

Option Strict On

Imports System

Class Tester199

Shared Sub Main()

Console.WriteLine("Enter Func2...")

Try

Console.WriteLine("Entering Try block...")

Throw New System.Exception()

Console.WriteLine("Exitintg Try block...")

Catch

Console.WriteLine("Exception caught and handled")

End Try

Console.WriteLine("Exit func2...")

End Sub 'Main

End Class 'Tester

115

'Catch Exception throwed from a Method

Option Strict On

Imports System

Class Tester200

Shared Sub Main()

Console.WriteLine("Enter func1...")

Try

Console.WriteLine("Entering Try block...")

Func1()

Console.WriteLine("Exiting Try block...")

Catch

Console.WriteLine("Exception caught and handled")

End Try

Console.WriteLine("Exit func1...")

End Sub

Public Shared Sub Func1()

Console.WriteLine("Enter Func2...")

Throw New System.Exception()

Console.WriteLine("Exit Func2...")

End Sub

End Class

'Catch different Exception with multiple catch statements

Imports System.IO



Dim y As Integer

Dim x As Integer

Dim z As Integer

116

Try

x = 1

y = 0

z = x / y

Catch e As DivideByZeroException

Console.WriteLine("You have attempted to divide by

zero!")

y = 2

z = x / y

Catch e As OverflowException

Console.WriteLine("You have encountered an

overflow exception. ")

y = 2

z = x / y

Catch e As System.Data.ConstraintException

Console.WriteLine("You have encountered a

constraint exception. ")

y = 2

z = x / y

Finally

Console.WriteLine(x & "/" & y & " = " & z)

End Try

End Sub

End Class

'Catch without Exception type



Dim strCaption As String

strCaption = "Answer"

Try

Console.WriteLine(strCaption.Substring(10, 1))

Catch

Console.WriteLine("An error has occurred.")

End Try

End Sub

End Class

117

'Catch custom exception

Public Class MyException

Inherits System.Exception

Sub New(ByVal Message As String)

MyBase.New(Message)

End Sub

End Class



Try

Console.WriteLine("About to generate custom

exception")

Throw (New MyException("** Custom Message **"))

Catch Ex As MyException

Console.WriteLine("Custom Exception thrown " &

Ex.Message)

End Try

End Sub

End Class

'Try Catch with Finally clause

Option Strict On

Imports System

Class Tester204

Public Shared Function DoDivide(ByVal a As Double, ByVal b

As Double) As Double

If b = 0 Then

Throw New System.DivideByZeroException()

End If

If a = 0 Then

118

Throw New System.ArithmeticException()

End If

Return a / b

End Function 'DoDivide

Shared Sub Main()

Try

Console.WriteLine("Open file here")

Dim a As Double = 5

Dim b As Double = 0

Console.WriteLine("{0} / {1} = {2}", a, b,

DoDivide(a, b))

Console.WriteLine("This line may or may not

print")

Catch e As System.DivideByZeroException

Console.WriteLine("DivideByZeroException caught!")

Catch

Console.WriteLine("Unknown exception caught!")

Finally

Console.WriteLine("Close file here.")

End Try

End Sub

End Class

'Finally always executes



DoesNotThrowException()

End Sub

Public Shared Sub DoesNotThrowException()

Try

Console.WriteLine("In DoesNotThrowException")

Catch

Console.WriteLine("This Catch never executes")

Finally

Console.WriteLine("Finally executed in

DoesNotThrowException")

End Try

119

Console.WriteLine("End of DoesNotThrowException")

End Sub ' DoesNotThrowException

End Class

'Finally after multiple catch statements

Module Module206

Sub Main()

Dim intItem1 As Integer = 0

Dim intItem2 As Integer = 128


Try

intResult = intItem2 / intItem1

Catch e As OverflowException

Console.WriteLine("An overflow exception

occurred.")

Catch e As OutOfMemoryException

Console.WriteLine("Out of memory.")

Catch e As IndexOutOfRangeException

Console.WriteLine("Array index out of range.")

Finally

Console.WriteLine("Finally")

End Try

End Sub

End Module

' Math.Sqrt and Atan2



Dim magnitude As Single

Dim radians As Single

magnitude = CSng(Math.Sqrt(100 ^ 2 + 120 ^ 2))

radians = CSng(Math.Atan2(100, 123))

120

Console.WriteLine(magnitude)

Console.WriteLine(radians)

End Sub

End Class

'Math. Cos and Sin



Dim X As Single

Dim Y As Single

X = CSng(Math.Cos(100))

Y = CSng(Math.Sin(100))

Console.WriteLine(X)

Console.WriteLine(Y)

End Sub

End Class

'Generating random integers.

Module Tester209

Sub Main()

Dim randomObject As Random = New Random()

Dim randomNumber As Integer

Dim output As String = ""

Dim i As Integer

For i = 1 To 20

randomNumber = randomObject.Next(1, 7)

output &= randomNumber & " "

121

If i Mod 5 = 0 Then ' is i a multiple of 5?

output &= vbCrLf

End If

Next

Console.WriteLine(output)

End Sub

End Module

'Math.Round



Dim digits As Integer

For digits = 0 To 5

Console.WriteLine(Math.Round(Math.PI, digits))

Next digits

End Sub

End Class

'Randomize

Option Strict On

Public Module RandomizeStatement

Public Sub Main()

Dim number As Double = 1.0325

Rnd(-1)

Randomize(number) ' Number is

any Double

For ctr As Integer = 1 To 10

Console.WriteLine(Rnd())

122

Next

End Sub

End Module

'Load Assembly from a url

imports System.Reflection ' necessary for

instantiating assemblies

Imports System.Windows.Forms



Try

Dim strUrl As String = "http" &

"://localhost/MultiFileAssyVB/vbDeploy.exe"

' dim strUrl as String =

"http" & "://localhost/MultiFileAssy/csDeploy.exe"

Dim a As [Assembly] = [Assembly].LoadFrom(strUrl)

Dim t As Type = a.GetType("Form1")

' dim t as Type =

a.GetType("csDeploy.Form1")

Dim o As Object = Activator.CreateInstance(t)

Dim frm As Form = CType(o, Form)

frm.Show()


Console.WriteLine(ex.ToString)

End Try

End Sub

End Class

'Get types from Assembly

123

Imports System.Reflection

Module Module214

Sub Main()

Dim thisAssembly As [Assembly] =

[Assembly].GetExecutingAssembly()

Console.Write("Types: ")

Dim TypeObj As Type

For Each TypeObj In thisAssembly.GetTypes()

Console.Write(TypeObj.Name & " ")

Next

End Sub

End Module

'Get Assembly: Code base, Full name, Entry point, Assembly

Cache, Location

Imports System.Reflection

Module Module21

Sub Main()

Dim thisAssembly As [Assembly] =

[Assembly].GetExecutingAssembly()

Console.WriteLine("Code base: " &

thisAssembly.CodeBase)

Console.WriteLine("Full name: " &

thisAssembly.FullName)

Console.WriteLine("Entry point: " &

thisAssembly.EntryPoint.ToString())

Console.WriteLine("From Global Assembly Cache: " &

thisAssembly.GlobalAssemblyCache)

Console.WriteLine("Location: " &

thisAssembly.Location)

End Sub

End Module

'Array declaration

124

Option Strict On

Public Module Arrays

Public Sub Main()

Dim arr As Array

Dim int() As Integer = {12, 16, 20, 24, 28, 32}

arr = CType(int, Array)

Dim byFours() As Integer = {12, 24, 36, 48}

Dim names() As String = {"K", "S", "S", "D", "N"}

Dim miscData() As Object = {"this", 12D, 16UI, "a"c}

Dim objArray() As Object

miscData = names

Dim myArray1a() As Integer ' Uninitialized array

Dim myArray1b As Integer() ' Uninitialized array

Dim myArray2(10) As Integer ' 1-dimensional array with

11 elements

Dim Employees1(,) As Object ' Uninitialized 2-D array

Dim Employees(200, 2) As Object ' 2-D array with 201

and 3 elements

Dim jagged1(9)() As String

Dim jagged2()() As String = New String(9)() {}

Dim myArray1arr As Array

Dim myArray2a As Array =

Array.CreateInstance(GetType(Integer), 10)

Dim members() As Integer = {3, 10}

Dim myArray3a As Array =

Array.CreateInstance(GetType(Integer), members)

End Sub

End Module

'Declaring and allocating an array

Module Tester216

Sub Main()

Dim i As Integer

Dim array As Integer() ' declare array variable

array = New Integer(9) {} ' allocate memory for array

Console.WriteLine("Subscript " & vbTab & "Value")

For i = 0 To array.GetUpperBound(0)

Console.WriteLine(i & vbTab & array(i))

125

Next

Console.WriteLine("The array contains " & _

array.Length & " elements.")

End Sub

End Module

'Initializing arrays

Module Tester217

Sub Main()

Dim i As Integer

Dim array1, array2 As Integer() ' declare two arrays

' initializer list specifies number of elements

' and value of each element

array1 = New Integer() {2, 7, 4, 8, 5, 14, 90, 70, 60,

37}

' allocate array2 based on length of array1

array2 = New Integer(array1.GetUpperBound(0)) {}

' set values in array2 by a calculation


array2(i) = 2 + 2 * i

Next

Console.WriteLine("Subscript " & vbTab & "Array1" &

vbTab & _

"Array2")

' display values for both arrays


Console.WriteLine(i & vbTab & array1(i) & vbTab &

array2(i))

Next

End Sub

End Module

126

'Display the contents of a single-dimension array



Dim sourceArray() As Integer = {1, 2, 3}



result.Append("{")

For counter = 0 To sourceArray.Length - 1

result.Append(sourceArray(counter).ToString())

If (counter < (sourceArray.Length - 1)) Then

result.Append(",")

Next counter

result.Append("}")


End Sub

End Class

'Assing array element value by using index



Dim arySalaries(15) As Integer

Dim aryNames(15) As String


aryNames(0) = "J"

arySalaries(0) = 34000

aryNames(1) = "B"


127

'Set other array elements here.

aryNames(15) = "P"




Console.WriteLine("Array element: " & intCounter &

vbCrLf & _

"Name: " & aryNames(intCounter) & vbCrLf &

_

"Salary: " & arySalaries(intCounter))

Next intCounter

End Sub

End Class

'Computing sum of elements in array.

Module Tester220

Sub Main()

Dim array As Integer() = New Integer() _

{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

Dim total As Integer = 0, i As Integer


total = total + array(i)

Next

Console.WriteLine("Total of array elements: " & total)

End Sub

End Module

128

'Initialize Array element during declaration

Option Strict On

Imports System




Me.empID = empID

End Sub


Return empID.ToString()

End Function

End Class

Class Tester227


Dim intArray As Integer() = {2, 4, 6, 8, 10}

Dim empArray As Employee23() = _

{New Employee23(5), New Employee23(7), New

Employee23(9)}

Console.WriteLine("The Integer array...")

Dim theInt As Integer

For Each theInt In intArray

Console.WriteLine(theInt.ToString())

Next theInt

Console.WriteLine("The employee array...")

Dim e As Employee23


Console.WriteLine(e.ToString())

Next e

End Sub 'Run

End Class

'Array Resize

129




Dim arrayInsert() As String = {"O", "A", "G", "B",

"B"}

' ----- Show the contents before insertion.

result.AppendLine("Before insertion:")

For Each fruit As String In arrayInsert

result.AppendLine(fruit)

Next fruit

' ----- Insert more fruit.

InsertArrayElement(Of String)(arrayInsert, 2,

"Lemons")

' ----- Show the contents after insertion.

result.AppendLine()

result.AppendLine("After insertion:")



Next fruit


End Sub

Public Shared Sub InsertArrayElement(Of T)( _

ByRef sourceArray() As T, _

ByVal insertIndex As Integer, _

ByVal newValue As T)

Dim newPosition As Integer


newPosition = insertIndex

If (newPosition < 0) Then newPosition = 0

If (newPosition > sourceArray.Length) Then _

newPosition = sourceArray.Length

Array.Resize(sourceArray, sourceArray.Length + 1)

For counter = sourceArray.Length - 2 To newPosition

Step -1

sourceArray(counter + 1) = sourceArray(counter)

Next counter

sourceArray(newPosition) = newValue

End Sub

End Class

130

'Insert element in the middle of an Array




Dim arrayInsert() As String = {"O", "A", "G", "B",

"B"}

' ----- Show the contents before insertion.

'result.AppendLine("Before insertion:")

Console.WriteLine("Before insertion")



Next fruit

' ----- Insert more fruit.

InsertArrayElement(Of String)(arrayInsert, 2,

"Lemons")

' ----- Show the contents after insertion.

result.AppendLine()

result.AppendLine("After insertion:")



Next fruit


End Sub

Public Shared Sub InsertArrayElement(Of T)( _

ByRef sourceArray() As T, _

ByVal insertIndex As Integer, _

ByVal newValue As T)



newPosition = insertIndex

If (newPosition < 0) Then newPosition = 0

If (newPosition > sourceArray.Length) Then _

newPosition = sourceArray.Length

Array.Resize(sourceArray, sourceArray.Length + 1)

For counter = sourceArray.Length - 2 To newPosition

Step -1

sourceArray(counter + 1) = sourceArray(counter)

Next counter

131

sourceArray(newPosition) = newValue

End Sub

End Class

'One dimesional array performance



Dim start_time As DateTime

Dim stop_time As DateTime


Dim num_items As Integer = 10000

Dim array1(0 To num_items - 1) As Integer

start_time = Now

For i As Integer = 0 To num_items - 1

array1(i) = i

Next i

stop_time = Now

elapsed_time = stop_time.Subtract(start_time)

Console.WriteLine(elapsed_time.TotalSeconds())

Erase array1

End Sub

End Class

'Two dimesional array performance



Dim start_time As DateTime

Dim stop_time As DateTime

132


Dim num_items As Integer = 10000

' Two-dimensional array.

Dim array2(0 To 0, 0 To num_items - 1) As Integer

start_time = Now

For i As Integer = 0 To num_items - 1

array2(0, i) = i

Next i

stop_time = Now

elapsed_time = stop_time.Subtract(start_time)

Console.WriteLine(elapsed_time.TotalSeconds())

Erase array2

End Sub

End Class

'Array Clone







"E", "F", "G", "H"}





' ----- Make a full, unique copy of all elements.

Dim arrayD() As String = arrayA.Clone

Console.WriteLine(Join(arrayD, ","))

End Sub

End Class

133

'Array length: negative

Option Strict On

Public Module ValidArray

Public Sub Main()

Dim emptyArray(-1) As String

For Each element As String In emptyArray

Console.WriteLine(element)

Next

End Sub

End Module

'Reorder the elements of an array in a random order



Dim arrayShuffle() As String = {"A", "B", "C", "D",

"E"}

For Each fruit As String In arrayShuffle

Console.WriteLine(fruit)

Next fruit

Shuffle(arrayShuffle)

For Each fruit As String In arrayShuffle


Next fruit

End Sub

Public Shared Sub Shuffle(ByRef shuffleArray() As Object)



Dim shuffleMethod As New Random

134

Dim tempObject As Object

For counter = 0 To shuffleArray.Length - 1

newPosition = shuffleMethod.Next(0,

shuffleArray.Length - 1)

tempObject = shuffleArray(counter)

shuffleArray(counter) = shuffleArray(newPosition)

shuffleArray(newPosition) = tempObject

Next counter

End Sub

End Class

'Swap elements in an array




Dim arraySwap() As String = {"A", "B", "C", "D", "E"}

Swap(arraySwap, 1, 3)

For Each fruit As String In arraySwap


Next fruit

End Sub

Public Shared Sub Swap(ByRef swapArray() As Object, _

ByVal first As Integer, ByVal second As Integer)

Dim tempObject As Object

tempObject = swapArray(first)

swapArray(first) = swapArray(second)

swapArray(second) = tempObject

End Sub

End Class

'Use For loop to initialize Integer array

135

Module Module230

Sub Main()

Dim Students(50) As Integer

Dim I As Integer

For I = 0 To 50

Students(I) = I

Next

For I = 0 To 50

Console.WriteLine(Students(I))

Next

End Sub

End Module

'Show and use the array boundaries



Dim aryNames(9) As String


'Show the array boundaries.

Console.WriteLine("LOWER BOUND: " &

aryNames.GetLowerBound(0))

Console.WriteLine("UPPER BOUND: " &

aryNames.GetUpperBound(0))

Console.WriteLine("LENGTH: " & aryNames.Length)

'Populate the array.

For intCounter = 0 To aryNames.GetUpperBound(0)

aryNames(intCounter) = "Element position = " &

intCounter

Next intCounter


For intCounter = 0 To aryNames.GetUpperBound(0)

Console.WriteLine("Element position = " &

intCounter)

136

Next intCounter

End Sub

End Class

'Use array UBound in For loop

Module Module232

Sub Main()

Dim Scores(2) As Integer

Scores(0) = 45

Scores(1) = 55

Scores(2) = 65

For intLoopIndex As Integer = 0 To UBound(Scores)

Console.WriteLine("Score(" & intLoopIndex & ") = "

& Scores(intLoopIndex))

Next intLoopIndex

End Sub

End Module

'GetUpperBound

Module Tester233

Sub Main()

Dim answer, rating As Integer

Dim output As String

Dim responses As Integer()

responses = New Integer() {1, 2, 6, 4, 8, 5, 9, 7, _

8, 10, 1, 6, 3, 8, 6, 10, 3, 8, 2, 7, 6, 5, 7, 6, _

8, 6, 7, 5, 6, 6, 5, 6, 7, 5, 6, 4, 8, 6, 8, 10}

' response frequency array (indices 0 through 10)

Dim frequency As Integer() = New Integer(10) {}

137

' count frequencies

For answer = 0 To responses.GetUpperBound(0)

frequency(responses(answer)) += 1

Next

Console.WriteLine("Rating " & vbTab & "Frequency ")

For rating = 1 To frequency.GetUpperBound(0)

Console.WriteLine(rating & vbTab &

frequency(rating))

Next

End Sub ' Main

End Module

'Array lower bound and upper bound

Option Strict On

Public Class CArray


Dim dims() As Integer = {10} ' Number of elements in

array

Dim bnds() As Integer = {50} ' Lower bound of array

Dim Scores As Array =

Array.CreateInstance(GetType(Integer), dims, bnds)

Console.WriteLine(UBound(Scores))

Console.WriteLine(LBound(Scores))

End Sub

End Class

'Get array lower bound, upper bound and length

Module Tester235

Sub Main()

Dim Values() As Integer = {100, 200, 300, 400, 500}

Dim MyValues(5) As Integer

Dim Prices() As Double = {25.5, 4.95, 33.4}

138

Dim I As Integer

For I = 0 To 4

Console.Write(Values(I) & " ")

Next

Console.WriteLine()

Console.WriteLine("Array length: " & Values.Length)

Console.WriteLine("Array lowerbound: " &

Values.GetLowerBound(0))

Console.WriteLine("Array upperbound: " &

Values.GetUpperBound(0))

End Sub

End Module

'Pass array

Imports System

Imports Microsoft.VisualBasic

Module Test236

Dim i As Integer

Public Sub AddOne(ByVal InputArray() As Integer)

For i = 0 To 3

InputArray(i) = InputArray(i) + 1

Next

End Sub

Public Sub AddTwo(ByVal InputArray() As Integer)

Dim tempArray() As Integer

tempArray = InputArray.Clone

For i = 0 To 3

tempArray(i) = tempArray(i) + 2

Next

End Sub

Sub Main()

Dim intArray() As Integer = {6, 8, 7, 6}

For i = 0 To 3

Console.WriteLine("{0}", intArray(i))

139

Next

AddOne(intArray)

For i = 0 To 3


Next

AddTwo(intArray)

For i = 0 To 3


Next

End Sub

End Module

'Testing the effects of passing array references using ByVal

and ByRef

Module Tester237

Sub Main()

Dim i As Integer

Dim firstArray As Integer()

Dim firstArrayCopy As Integer()

firstArray = New Integer() {1, 2, 3}

firstArrayCopy = firstArray

For i = 0 To firstArray.GetUpperBound(0)

Console.Write(firstArray(i) & " ")

Next

FirstDouble(firstArray)

For i = 0 To firstArray.GetUpperBound(0)

Console.Write(firstArray(i) & " ")

Next

If firstArray Is firstArrayCopy Then

Console.WriteLine("The references are equal.")

Else

Console.WriteLine("The references are not equal.")

End If

Dim secondArray As Integer()

Dim secondArrayCopy As Integer()

secondArray = New Integer() {1, 2, 3}

secondArrayCopy = secondArray

140

For i = 0 To secondArray.GetUpperBound(0)

Console.Write(secondArray(i) & " ")

Next

SecondDouble(secondArray)

For i = 0 To secondArray.GetUpperBound(0)

Console.Write(secondArray(i) & " ")

Next

If secondArray Is secondArrayCopy Then

Console.WriteLine("The references are equal.")

Else

Console.WriteLine("The references are not equal.")

End If

End Sub ' Main

Sub FirstDouble(ByVal array As Integer())

Dim i As Integer


array(i) *= 2

Next

array = New Integer() {11, 12, 13}

End Sub

Sub SecondDouble(ByRef array As Integer())

Dim i As Integer


array(i) *= 2

Next

array = New Integer() {11, 12, 13}

End Sub

End Module

'Array.GetLength, Array.GetUpperBound



Dim aryStatistics(14) As Integer

Console.WriteLine("RANK: " & aryStatistics.Rank)

141

'Dimensions in array.

Console.WriteLine("TOTAL ELEMENTS: " &

aryStatistics.Length) 'Total elements in array.

Console.WriteLine("ELEMENTS IN FIRST: " &

aryStatistics.GetLength(0)) 'Elements in first dimension.

Console.WriteLine("ELEMENTS IN SECOND: " &

aryStatistics.GetLength(1)) 'Elements in second dimension.

Console.WriteLine("LAST INDEX IN FIRST: " &

aryStatistics.GetUpperBound(0)) 'Last index in the first

dimension.

Console.WriteLine("LAST INDEX IN SECOND: " &

aryStatistics.GetUpperBound(1)) 'Last index in the second

dimension.

End Sub

End Class

'Array.IndexOf



Dim values() As Integer = {10, 20, 30, 40, 50, 60, 40}

'For i As Integer = 0 To 10

' values(i) = i

'Next i

Console.WriteLine(Array.IndexOf(values, 40).ToString)

Console.WriteLine(Array.LastIndexOf(values,

40).ToString)

End Sub

End Class

'Array.LastIndexOf



142

Dim values(10) As Integer


values(i) = i

Next i

Console.WriteLine(Array.LastIndexOf(values,

3).ToString)

End Sub

End Class

'Reverse array elements

Module Tester241

Sub Main()


'Dim MyValues(5) As Integer

'Dim Prices() As Double = {25.5, 4.95, 33.4}

Dim I As Integer

For I = 0 To 4


Next

Console.WriteLine()

Array.Reverse(Values)

For I = 0 To 4


Next

Console.WriteLine()

Array.Sort(Values)

For I = 0 To 4


Next

End Sub

End Module

'Use Array.Sort() to sort object array

143

Imports System

Module MyModule242

Sub Main()

Dim salaries(4) As Salary

salaries(0) = New Salary(9)



salaries(3) = salaries(2)


Console.WriteLine("Unsorted array:")

Dim salary As Salary

For Each salary In salaries

Console.WriteLine("{0}", salary)

Next

Array.Sort(salaries)

Console.WriteLine(vbCrLf & "Sorted array:")

For Each salary In salaries

Console.WriteLine("{0}", salary)

Next

End Sub

End Module

Structure Salary


Private value As Integer

Public Sub New(ByVal amount As Double)

Me.value = CInt(amount * 100)

End Sub

Public Function CompareTo(ByVal other As Object) As

Integer Implements IComparable.CompareTo

Dim m2 As Salary = CType(other, Salary)

If Me.value < m2.value Then

Return -1

ElseIf Me.value = m2.value Then

Return 0

Else

Return +1

End If

End Function


Return Me.value

144

End Function

End Structure

'Copy array elements from one array to another

Module Tester243

Sub Main()


Dim MyValues(5) As Integer

'Dim Prices() As Double = {25.5, 4.95, 33.4}

Dim I As Integer

For I = 0 To 4


Next

Console.WriteLine()

' Copy one array to another

Values.CopyTo(MyValues, 0)

For I = 0 To 4

Console.Write(MyValues(I) & " ")

Next

End Sub

End Module

'Array.Copy: Copy elements by position







"E", "F", "G", "H"}





' ----- Copy elements by position.

Array.Copy(arrayB, 0, arrayA, 1, 3)


145

End Sub

End Class

'Array SetValue and GetValue

Imports System.Collections.Generic



Dim squares As Array =

Array.CreateInstance(GetType(Integer), 11)


squares.SetValue(i * i, i)

Next i


Console.WriteLine(squares.GetValue(i).ToString)

Next i

End Sub

End Class

'Populate Object array

Option Strict On

Imports System




Me.empID = empID

End Sub

End Class

Class Tester246

Shared Sub Main()

Dim intArray As Integer()

146

Dim empArray As Employee246()

intArray = New Integer(5) {}

empArray = New Employee246(3) {}

Dim i As Integer

For i = 0 To empArray.Length - 1

empArray(i) = New Employee246(i + 5)

i = i + 1

Next

End Sub

End Class

'Reverse the contents of an array



Dim arrayReverse() As String = {"A", "B", "C", "D",

"E"}

For Each fruit As String In arrayReverse


Next fruit

Array.Reverse(arrayReverse)

For Each fruit As String In arrayReverse


Next fruit

End Sub

End Class

'Array Reverse and Sort

Option Strict On

Imports System

Class Tester248

Public Shared Sub DisplayArray(ByVal theArray() As Object)

Dim obj As Object

147

For Each obj In theArray

Console.WriteLine("Value: {0}", obj)

Next obj

Console.WriteLine(ControlChars.Lf)

End Sub


Dim myArray As [String]() = {"W", "s", "J", "t"}

Console.WriteLine("Display myArray...")

DisplayArray(myArray)

Console.WriteLine("Reverse and display myArray...")

Array.Reverse(myArray)

DisplayArray(myArray)

Dim myOtherArray As [String]() = {"W", "d", "e", "s",

"o", "e", "f", "t"}

Console.WriteLine("Display myOtherArray...")

DisplayArray(myOtherArray)

Console.WriteLine("Sort and display myOtherArray...")

Array.Sort(myOtherArray)

DisplayArray(myOtherArray)

End Sub 'Main

End Class 'Tester

'Array.BinarySearch



Shared Sub Main()

Dim integerValues As Integer() = {1, 2, 3, 4, 5, 6}

Dim integerElement As Integer

For Each integerElement In integerValues

Console.WriteLine(integerElement)

Next

Dim result As Integer =

Array.BinarySearch(integerValues, 5)

If result >= 0 Then

Console.WriteLine("5 found at element " & result &

" in integerValues")

Else

Console.WriteLine("5 not found" & " in

148

integerValues")

End If

End Sub

End Class

'Array.Sort and Array.IndexOf




Dim StringArray() As String = {"This", "is", "a",

"test"}

Dim E As IEnumerator = StringArray.GetEnumerator()

While (E.MoveNext())

Console.WriteLine(E.Current())

End While

Dim NewArray(StringArray.Length) As String

Array.Copy(StringArray, NewArray, StringArray.Length)

Console.WriteLine(Array.IndexOf(NewArray, "a"))

End Sub

End Class

'Linear search of an array



Dim array1 As Integer() = New Integer(19) {}

Dim randomNumber As Random = New Random()

Dim i As Integer

' creates string containing 11 random numbers

149


array1(i) = randomNumber.Next(1000)

Console.Write(array1(i) & " ")

Next

Console.WriteLine("")

Dim searchKey As Integer = 12

Dim element As Integer = LinearSearch(searchKey,

array1)

If element <> -1 Then

Console.WriteLine("Found Value in index " &

element)

Else

Console.WriteLine("Value Not Found")

End If

End Sub

Shared Function LinearSearch(ByVal key As Integer, _

ByVal numbers As Integer()) As Integer

Dim n As Integer

' structure iterates linearly through array

For n = 0 To numbers.GetUpperBound(0)

If numbers(n) = key Then

Return n

End If

Next

Return -1

End Function ' LinearSearch

End Class

'Demonstrating binary search of an array


Shared array1 As Integer() = New Integer(14) {}


150

Dim i As Integer


array1(i) = 2 * i

Next

Dim searchKey As Integer = 8

Dim element As Integer = BinarySearch(array1,

searchKey)

If element <> -1 Then

Console.WriteLine("Found value in element " &

element)

Else

Console.WriteLine("Value not found")

End If

End Sub

' performs binary search

Shared Function BinarySearch(ByVal array As Integer(), _

ByVal key As Integer) As Integer

Dim low As Integer = 0 ' low index

Dim high As Integer = array.GetUpperBound(0) ' high

index

Dim middle As Integer ' middle index

While low <= high

middle = (low + high) \ 2

If key = array(middle) Then ' match

Return middle

ElseIf key < array(middle) Then ' search low end

high = middle - 1 ' of array

Else

low = middle + 1

End If

End While

Return -1 ' search key not found

End Function ' BinarySearch

End Class

'Initializing multi-dimensional arrays

151

Module Tester254

Sub Main()

Dim i, j As Integer

' create rectangular two-dimensional array

Dim array1 As Integer(,)

array1 = New Integer(,) {{1, 2, 3}, {4, 5, 6}}

' create jagged two-dimensional array

Dim array2 As Integer()() = New Integer(2)() {}

array2(0) = New Integer() {1, 2}

array2(1) = New Integer() {3}

array2(2) = New Integer() {4, 5, 6}


For j = 0 To array1.GetUpperBound(1)

Console.Write(array1(i, j) & " ")

Next


Next


For j = 0 To array2(i).GetUpperBound(0)

Console.WriteLine(array2(i)(j) & " ")

Next


Next

End Sub

End Module

'Rectangular Array

Option Strict On

Imports System

Class Tester255

Shared Sub Main()

152

Const rowsUB As Integer = 4

Const columnsUB As Integer = 3

Dim rectangularArray(rowsUB, columnsUB) As Integer

Dim i As Integer

For i = 0 To rowsUB - 1

Dim j As Integer

For j = 0 To columnsUB - 1

rectangularArray(i, j) = i + j

Next j

Next i


Dim j As Integer



"rectangularArray[{0},{1}] = {2}", _

i, j, rectangularArray(i, j))

Next j

Next i

End Sub

End Class

'Define and initialize the two dimensional array

Imports System

Class Tester25


Const rowsUB As Integer = 4

Const columnsUB As Integer = 3

Dim rectangularArray As Integer(,) = _

{{0, 1, 2}, {3, 4, 5}, {6, 7, 8}, {9, 10, 11}}

Dim i As Integer


Dim j As Integer



"rectangularArray[{0},{1}] = {2}", _

i, j, rectangularArray(i, j))

Next j

Next i

End Sub 'Run

153

End Class

'Jagged two-dimensional array example.

Module Tester257

Dim lastStudent, lastExam As Integer

Sub Main()

Dim i As Integer

' jagged array with 3 rows of exam scores

Dim gradeArray()() As Integer

gradeArray(0) = New Integer() {7, 8, 6, 3}



' upper bounds for array manipulations

lastStudent = gradeArray.GetUpperBound(0)

lastExam = gradeArray(0).GetUpperBound(0)

Console.WriteLine("Lowest grade: " & _

Minimum(gradeArray) & vbCrLf & "Highest grade: " &

_

Maximum(gradeArray))

For i = 0 To lastStudent

Console.WriteLine("Average for student " & _

i & " is " & Average(gradeArray(i)))

Next

End Sub ' Main

Function Minimum(ByVal grades As Integer()()) _

As Integer

Dim lowGrade As Integer = 100

Dim i, j As Integer


For j = 0 To lastExam

If grades(i)(j) < lowGrade Then

lowGrade = grades(i)(j)

End If

Next

154

Next

Return lowGrade

End Function ' Minimum

Function Maximum(ByVal grades As Integer()()) _

As Integer

Dim highGrade As Integer = 0

Dim i, j As Integer


For j = 0 To lastExam

If grades(i)(j) > highGrade Then

highGrade = grades(i)(j)

End If

Next

Next

Return highGrade

End Function ' Maximum

Function Average(ByVal setOfGrades As Integer()) _

As Double

Dim i As Integer, total As Integer = 0

For i = 0 To lastExam

total += setOfGrades(i)

Next

Return total / setOfGrades.Length

End Function ' Average

End Module

'Declare the jagged array as 4 rows high

Option Strict On

Imports System

Public Class jaggedarray


Const rowsUB As Integer = 3 ' upper bounds

Const rowZero As Integer = 5

Const rowOne As Integer = 2

Const rowTwo As Integer = 3

Const rowThree As Integer = 5

Dim i As Integer

155

Dim jaggedArray(rowsUB)() As Integer

ReDim jaggedArray(0)(rowZero)

ReDim jaggedArray(1)(rowOne)

ReDim jaggedArray(2)(rowTwo)

ReDim jaggedArray(3)(rowThree)

jaggedArray(0)(3) = 15









For i = 0 To rowZero

Console.WriteLine("jaggedArray(0)({0}) = {1}", _

i, jaggedArray(0)(i))

Next

For i = 0 To rowOne



Next

For i = 0 To rowTwo



Next

For i = 0 To rowThree



Next

End Sub

End Class

'Reference elements in two dimensional array



Dim aryBoard(9, 9) As Integer

156

'Move the element.

aryBoard(0, 0) = 0

aryBoard(2, 4) = 1

'Check for the element.

If aryBoard(0, 0) = 1 Then

Console.WriteLine("The piece was found.")

Else

Console.WriteLine("The piece was not found.")

End If

End Sub

End Class

'Use For Each/Next to find an element in a two dimension array

Module modForEach

Sub Main()

Dim gradeArray As Integer(,) = New Integer(,) _

{{77, 68, 86, 73}, {98, 87, 89, 81}, {70, 90, 86,

81}}

Dim grade As Integer

Dim lowGrade As Integer = 100

For Each grade In gradeArray

If grade < lowGrade Then

lowGrade = grade

End If

Next

Console.WriteLine("The minimum grade is: {0}",

lowGrade)

End Sub ' Main

End Module

'Set the array of arrays

157



Dim aryIntArray(9) As Integer

Dim aryStrArray(99) As String

Dim aryBigArray(1) As Object


'Populate array aryIntArray.


aryIntArray(intCounter) = intCounter

Next

'Populate array aryStrArray.


aryStrArray(intCounter) = "ITEM: " &

intCounter.ToString("0000")

Next

'Set the array of arrays.

aryBigArray(0) = aryIntArray

aryBigArray(1) = aryStrArray

'Display some array values.

Console.WriteLine(aryBigArray(0)(7))

Console.WriteLine(aryBigArray(1)(16))

End Sub

End Class

'ReDim an array

Module Module262

Sub Main()

Dim Scores() As Integer

ReDim Scores(1)

Scores(0) = 25

Scores(1) = 75

ReDim Preserve Scores(5)

Scores(2) = 95

Scores(3) = 35

Scores(4) = 65

Scores(5) = 85

Console.WriteLine("Scores(3) = " & Scores(3))

158

End Sub

End Module

'Redim Preserve array

Option Strict On

Public Module modMain263

Public Sub Main()

Dim PowerOf2() As Integer = {0, 1, 2, 4, 8, 16, 32,

64, 128, 256, 512, 1024}

ReDim Preserve PowerOf2(PowerOf2.GetUpperBound(0) \ 2)

For Each int As Integer In PowerOf2

Console.Write("--{0}--", int)

Next

End Sub

End Module

'ReDim string array length



Dim DaysOfTheWeek() As String

ReDim DaysOfTheWeek(7)

DaysOfTheWeek(0) = "Monday"

DaysOfTheWeek(1) = "Tuesday"

DaysOfTheWeek(2) = "Wednesday"

DaysOfTheWeek(3) = "Thursday"

DaysOfTheWeek(4) = "Friday"

DaysOfTheWeek(5) = "Saturday"

DaysOfTheWeek(6) = "Sunday"

Console.WriteLine(DaysOfTheWeek(1))

159

End Sub

End Class

'Dynamic array

Option Strict On

Public Class DynamicArray


Dim index As Integer = 10

Dim arr(index) As Integer

arr(index) = CInt(index ^ 2)

index = 20

ReDim Preserve arr(index)

arr(index) = CInt(index ^ 2)

index = 10

ReDim Preserve arr(index)

Console.WriteLine(arr(index))

End Sub

End Class

'Dimension the array at runtime



Dim aryDynArray() As Integer



'Dimension the array at runtime.

intResult = 12

ReDim aryDynArray(intResult - 1)

Console.WriteLine("Array size is: " &

aryDynArray.Length)


160

For intCounter = 0 To aryDynArray.GetUpperBound(0)

aryDynArray(intCounter) = intCounter + 100

Next intCounter

End Sub

End Class

'Redimension the array and preserve its element values



Dim aryDynArray() As Integer



'Dimension the array at runtime.

intResult = 12

ReDim aryDynArray(intResult - 1)


aryDynArray.Length)


For intCounter = 0 To aryDynArray.GetUpperBound(0)

aryDynArray(intCounter) = intCounter + 100

Next intCounter

'Redimension the array and preserve its element

values.

ReDim Preserve

aryDynArray(aryDynArray.GetUpperBound(0) + 1)


aryDynArray.Length)

Console.WriteLine("First array value is: " &

aryDynArray(0))

'Erase the array.

Erase aryDynArray

End Sub

End Class

161

'Use ReDim Preserve to add elements to an array



Dim growingArray() As String = Nothing

' ----- Add elements to the array.

For counter As Integer = 0 To 2

ReDim Preserve growingArray(counter)

growingArray(counter) = (counter + 1).ToString

Next counter

' ----- Display the results.

For Each workText As String In growingArray

Console.WriteLine(workText)

Next workText

End Sub

End Class

'Inserting items into a collection by index



Dim wordCollection As New Collection

wordCollection.Add("This")

wordCollection.Add("is")

wordCollection.Add("a")

wordCollection.Add("collection")

wordCollection.Add("of")

wordCollection.Add("words")

' ----- Insert a word after item 3.

wordCollection.Add("slightly", , , 3)

' ----- Insert a word before item 5.

wordCollection.Add("longer", , 5)

For Each word As String In wordCollection

Console.WriteLine(word)

Next word

162

End Sub

End Class

' Add key value pair to Collection

Option Strict On


Public Class Collect


Dim sta As New Collection

sta.Add("New York", "NY")

sta.Add("Michigan", "MI")

sta.Add("New Jersey", "NJ")

sta.Add("Massachusetts", "MA")

For Each stcode As String In sta

Console.WriteLine(stcode)

Next

End Sub

End Class

'Store objects in Collection and retrieve by key and index

Imports System


Private myEmpID As Integer


Me.myEmpID = empID

End Sub 'New


Return myEmpID.ToString()

End Function 'ToString

Public Property EmpID() As Integer

Get

Return myEmpID

End Get

163


myEmpID = Value

End Set

End Property

End Class 'Employee

Class Tester271

Shared Sub Main()

Dim intCollection As New Collection()

Dim empCollection As New Collection()

Dim empCollection2 As New Collection()

Dim i As Integer

For i = 0 To 4

empCollection.Add(New Employee271(i + 100))

intCollection.Add((i * 5))

Next i

empCollection2.Add(New Employee271(1), "G")

empCollection2.Add(New Employee271(2), "J")

empCollection2.Add(New Employee271(3), "T")

For Each i In intCollection

Console.Write("{0} ", i.ToString())

Next i

Console.WriteLine()

Console.WriteLine("Employee collection...")

Dim e As Employee

For Each e In empCollection

Console.Write("{0} ", e.ToString())

Next e

Console.WriteLine()

Console.WriteLine("Employee collection 2...")

For Each e In empCollection2


Next e

Console.WriteLine()

Dim emp As Employee

emp = empCollection2.Item("J")

Console.WriteLine(emp.ToString())

emp = empCollection2.Item(1)

Console.WriteLine("Index(1) retrieved empID {0}",

emp.ToString())

End Sub

End Class

164

'Get Enumerator from Collection


Public Class Enumerate


Dim weights As New Collection

Dim iterator As IEnumerator

weights.Add("ounces", "oz")

weights.Add("pounds", "lbs")

weights.Add("kilograms", "kg")

weights.Add("milligrams", "mg")

iterator = weights.GetEnumerator

Do While iterator.MoveNext

Console.WriteLine(iterator.Current)

Loop

End Sub

End Class

'Deleting the members of a collection

Option Strict On

Public Module CollectionTest

Public Sub Main()

Dim weights As New Collection

weights.Add("ounces", "oz")

weights.Add("pounds", "lbs")

weights.Add("kilograms", "kg")

weights.Add("milligrams", "mg")

For ordinal As Integer = weights.Count To 1 Step -1

weights.Remove(ordinal)

Next

Console.WriteLine("The collection now has {0} items.",

weights.Count)

End Sub

End Module

165

'Remove from Collection



Dim employees As New Collection

employees.Add(New Employee274("A"))

employees.Add(New Manager("B"))

employees.Add(New Manager("C"))

employees.Add(New Employee274("D"))

For Each emp As Employee274 In employees

Console.WriteLine(emp.Name)

Next emp

For i As Integer = employees.Count To 1 Step -1

Dim emp As Employee274 = CType(employees(i),

Employee274)

If emp.IsManager Then employees.Remove(i)

Next i

For Each emp As Employee274 In employees

Console.WriteLine(emp.Name)

Next emp

End Sub

End Class



Public Sub New(ByVal new_name As String)

Name = new_name

End Sub

Public Overridable Function IsManager() As Boolean

Return False

End Function

End Class

Public Class Customer



Name = new_name

End Sub

End Class

166

Public Class Manager

Inherits Employee274


MyBase.new(new_name)

End Sub

Public Overrides Function IsManager() As Boolean

Return True

End Function

End Class

'Scanning items in a collection



Dim numberCollection As New Collection

numberCollection.Add(14, "C")

numberCollection.Add(25, "D")

numberCollection.Add(36, "E")

numberCollection.Add(47, "A")

numberCollection.Add(58, "B")

' ----- Scan the collection with a loop counter.

' Collections are base-1, not base-0.

For counter As Integer = 1 To numberCollection.Count

Console.WriteLine(numberCollection(counter))

Next counter

' ----- Scan the collection by item.

For Each number As Integer In numberCollection

Console.WriteLine(number)

Next number

' ----- Retrieve items by key.

Console.WriteLine(numberCollection("A"))

Console.WriteLine(numberCollection("B"))

Console.WriteLine(numberCollection("C"))

Console.WriteLine(numberCollection("D"))

Console.WriteLine(numberCollection("E"))

End Sub

167

End Class

'Add user defined object to ArrayList


Structure Person276

Dim strLastName As String

Dim strFirstName As String

Dim strPhone As String

Dim strEMail As String

End Structure



Dim alPersons As New ArrayList

Dim udtPerson As New Person276

'Add the first person.

With udtPerson

.strLastName = "S"

.strFirstName = "J"

.strPhone = "5"

.strEMail = "[email protected]"

End With

alPersons.Add(udtPerson)

'Add the second person.

With udtPerson

.strLastName = "J"

.strFirstName = "S"

.strPhone = "5"


End With


'Create the third person.

With udtPerson

.strLastName = "J"

.strFirstName = "K"

.strPhone = "5"


End With

'Insert the third person, but first check if they

already exists.

168

If Not alPersons.Contains(udtPerson) Then

alPersons.Insert(1, udtPerson)

End If

'Remove the first person.

alPersons.RemoveAt(0)

'Display the array list values.

Console.WriteLine("The array list contains " &

alPersons.Count & " elements.")

For Each udtPerson In alPersons

Console.WriteLine("NAME: " &

udtPerson.strFirstName & " " & udtPerson.strLastName)

Next udtPerson

End Sub

End Class

'Add different data types to ArrayList


Public Class AddElementsToArrayLista


Dim alist1 As New ArrayList()

alist1.Add("Hello") 'Add a System.String

alist1.Add(714) 'Add a System.Int32

alist1.Add(New DateTime(2003, 1, 1)) 'Add a

System.DateTime

alist1.Add(#1/1/2003#) 'Add a System.DateTime

alist1.Add(4.5) 'Add a System.Double

alist1.Add(4.5F) 'Add a System.Single

Dim o As Object

For Each o In alist1

Console.WriteLine(o & ": " &

o.GetType().ToString())

Next

End Sub

End Class

169

'Use ArrayList to store objects

Option Strict On

Imports System



Private myEmpID As Integer


Me.myEmpID = empID

End Sub 'New


Return myEmpID.ToString()

End Function 'ToString

Public Property EmpID() As Integer

Get

Return myEmpID

End Get


myEmpID = Value

End Set

End Property

End Class 'Employee

Class Tester278

Shared Sub Main()

Dim empArray As New ArrayList()

Dim intArray As New ArrayList()

Dim i As Integer

For i = 0 To 4

empArray.Add(New Employee278(i + 100))

intArray.Add((i * 5))

Next i

For Each i In intArray

Console.Write("{0} ", i.ToString())

Next i


Dim e As Employee



170

Next e


Console.WriteLine("empArray.Capacity: {0}",

empArray.Capacity)

End Sub

End Class

'Use For Each to loop through the ArrayList


Structure Person279





End Structure






With udtPerson

.strLastName = "S"

.strFirstName = "J"

.strPhone = "5"


End With



With udtPerson

.strLastName = "J"

.strFirstName = "S"

.strPhone = "5"


End With



With udtPerson

.strLastName = "J"

171

.strFirstName = "K"

.strPhone = "5"


End With


already exists.



End If









Next udtPerson

End Sub

End Class

'Convert ArrayList to array




Dim array_list As New ArrayList

array_list.Add("A")

array_list.Add("B")

array_list.Add("C")

' Array object of objects.

Dim astring_array As Array

astring_array = array_list.ToArray()

End Sub

End Class

'Use DirectCast to convert ArrayList to array

172




Dim array_list As New ArrayList

array_list.Add("A")

array_list.Add("B")

array_list.Add("C")

' Array of strings.

Dim string_array() As String

string_array =

DirectCast(array_list.ToArray(GetType(String)), String())

End Sub

End Class

'Use ArrayList.Contains to check if a object already exists


Structure Person282





End Structure






With udtPerson

.strLastName = "S"

.strFirstName = "J"

.strPhone = "5"


End With



With udtPerson

.strLastName = "J"

.strFirstName = "S"

.strPhone = "5"

173


End With



With udtPerson

.strLastName = "J"

.strFirstName = "K"

.strPhone = "5"


End With


already exists.



End If









Next udtPerson

End Sub

End Class

'Remove element in an ArrayList by index


Structure Person283





End Structure


174





With udtPerson

.strLastName = "S"

.strFirstName = "J"

.strPhone = "5"


End With



With udtPerson

.strLastName = "J"

.strFirstName = "S"

.strPhone = "5"


End With



With udtPerson

.strLastName = "J"

.strFirstName = "K"

.strPhone = "5"


End With


already exists.



End If









Next udtPerson

End Sub

End Class

175

'SortedList




Dim jobs As New SortedList

jobs.Add("02", "Two")

jobs.Add("10", "Ten")

jobs.Add("01", "One")

jobs.Add("06", "Six")

For i As Integer = 0 To jobs.Count - 1

Console.WriteLine(jobs.GetKey(i).ToString() & ": "

& _

jobs.GetByIndex(i).ToString())

Next i

jobs.Clear()

jobs.Add(2, "Two")

jobs.Add(10, "Ten")

jobs.Add(1, "One")

jobs.Add(6, "Six")

For i As Integer = 0 To jobs.Count - 1

Console.WriteLine(jobs.GetKey(i).ToString() & ": "

& _

jobs.GetByIndex(i).ToString())

Next i

End Sub

End Class

'Add value pair to Hashtable and get value back by key

Imports System


176

Class Test285

Shared Sub Main()

Dim myTable As New Hashtable()

myTable.Item("A") = 1

myTable.Item("B") = 44

myTable.Item("C") = 43

myTable.Item("D") = 33

myTable.Item("E") = 39

Dim Country As String = "C"

Dim Code As Integer = myTable.Item(Country)

Console.WriteLine(Code)

End Sub

End Class

'Retrieve single value from Hashtable by key

Option Strict On



Public Sub Main()

Dim airports As New Hashtable

airports.Add("JFK", "John F. Kennedy, New York")

airports.Add("LAX", "Los Angeles International, Los

Angeles")

airports.Add("ORD", "O'Hare International, Chicago")

airports.Add("LHR", "Heathrow Airport, London")

Console.WriteLine(airports.Item("JFK"))

End Sub

End Module

'Find value and key in a Hashtable

177


Public Module Hasher

Dim Tablet As Hashtable = New Hashtable()

Sub Main()

AddToTable()

FindItem("AAA")

FindKey("BBB")

End Sub

Public Sub AddToTable()

Tablet.Add("333", "WWWW")

Tablet.Add("444", "AAA")

Tablet.Add("BBB", "I386")

End Sub

Public Sub FindItem(ByVal item As String)

If Tablet.ContainsValue(item) Then

Console.WriteLine("Found {0} in the hashtable.",

item)

End If

End Sub

Public Sub FindKey(ByVal key As String)

If Tablet.ContainsKey(key) Then

Console.WriteLine("Found {0} in the list.", key)

End If

End Sub

End Module

'Use For Each to loop through all keys in Hashtable




Dim myTable As New Hashtable

Dim objKey As Object

Dim objValue As Object

'Populate the hash table.

myTable.Add("H", 1)

myTable.Add("L", 2)

178

'Check before inserting another value.

If Not myTable.ContainsKey("A") Then

myTable.Add("A", 78)

End If

'Remove a value.

myTable.Remove("L")

'Display the hash table values.

Console.WriteLine("The hash table contains " &

myTable.Count & " elements.")

For Each objKey In myTable.Keys

objValue = myTable.Item(objKey)

Console.WriteLine("ELEMENT KEY: " &

objKey.ToString & vbCrLf & _

"ELEMENT VALUE: " & objValue.ToString)

Next objKey

End Sub

End Class

'Queue

Option Strict On



Public Sub Main()

Dim waitingPassengers As New Queue

Console.WriteLine(waitingPassengers.Count)

waitingPassengers.Enqueue("a")

'waitingPassengers.Enqueue("b")

Console.WriteLine(waitingPassengers.Peek())

Console.WriteLine(waitingPassengers.Count)

Console.WriteLine(waitingPassengers.Dequeue())

End Sub

179

End Module

'Enqueue, Dequeue and Peek

Imports System


Class Tester290

Public Sub Run()

End Sub 'Run

Public Shared Sub DisplayValues(ByVal myCollection As

IEnumerable)

Dim myEnumerator As IEnumerator =

myCollection.GetEnumerator()

While myEnumerator.MoveNext()

Console.WriteLine("{0} ", myEnumerator.Current)

End While

Console.WriteLine()

End Sub 'DisplayValues

Shared Sub Main()

Dim intQueue As New Queue()

' populate the array

Dim i As Integer

For i = 0 To 4

intQueue.Enqueue((i * 5))

Next i

' Display the Queue.

Console.WriteLine("intQueue values:")

DisplayValues(intQueue)

' Remove an element from the queue.

Console.WriteLine("(Dequeue) {0}", intQueue.Dequeue())




' Remove another element from the queue.

Console.WriteLine("(Dequeue) {0}", intQueue.Dequeue())



180


' View the first element in the

' Queue but do not remove.

Console.WriteLine("(Peek) {0}", intQueue.Peek())




End Sub 'Main

End Class 'Tester

'Queue.Enqueue and ToArray



Private Shared m_Queue As New Queue


m_Queue.Enqueue("A")

DisplayQueue()

m_Queue.Enqueue("B")

DisplayQueue()

m_Queue.Enqueue("C")

DisplayQueue()

Dim txt As String = DirectCast(m_Queue.Dequeue(),

String)


DisplayQueue()

End Sub

Private Shared Sub DisplayQueue()

For Each str As String In m_Queue.ToArray()

Console.WriteLine(str)

Next str

End Sub

End Class

'Stack




Dim txt As String = "asdf"

181

Dim letter_stack As New Stack

For i As Integer = 0 To txt.Length - 1

Console.WriteLine(i)

letter_stack.Push(txt.Substring(i, 1))

Next

'letter_stack.Pop()

Do While letter_stack.Count > 0

Console.WriteLine(DirectCast(letter_stack.Pop(),

String))

Loop

End Sub

End Class

'Stack: Push, Pop and Peek

Option Strict On

Imports System


Class Tester293


IEnumerable)

Dim o As Object

For Each o In myCollection

Console.WriteLine(o)

Next o

End Sub 'DisplayValues

Shared Sub Main()

Dim intStack As New Stack()

' populate the stack

Dim i As Integer

For i = 0 To 7

intStack.Push((i * 5))

Next i

' Display the Stack.

Console.WriteLine("intStack values:")

DisplayValues(intStack)

' Remove an element from the stack.

182

Console.WriteLine("(Pop){0}", intStack.Pop())




' Remove another element from the stack.

Console.WriteLine("(Pop){0}", intStack.Pop())




' View the first element in the

' Stack but do not remove.

Console.WriteLine("(Peek) {0}", intStack.Peek())




End Sub 'Main

End Class 'Tester

'Convert and Copy Elements in a Stack to an Array

Option Strict On

Imports System


Class Tester294


IEnumerable)

Dim o As Object

For Each o In myCollection

Console.WriteLine(o)

Next o

End Sub

Shared Sub Main()

Dim intStack As New Stack()

Dim i As Integer

For i = 1 To 4

intStack.Push((i * 5))

Next i

183



Const arraySize As Integer = 10

Dim testArray(arraySize) As Integer

For i = 1 To arraySize - 1

testArray(i) = i * 100

Next i

Console.WriteLine("Contents of the test array")

DisplayValues(testArray)

intStack.CopyTo(testArray, 3)

Console.WriteLine("TestArray after copy: ")

DisplayValues(testArray)

Dim myArray As Object() = intStack.ToArray()

Console.WriteLine("The new array:")

DisplayValues(myArray)

End Sub

End Class

'Using generic methods to print arrays of different types

Module Tester295

Sub Main()

Dim integerArray As Integer() = {1, 2, 3, 4, 5, 6}

Dim doubleArray As Double() = {1.1, 2.2, 3.3, 4.4,

5.5, 6.6, 7.7}

Dim charArray As Char() = {"H"c, "E"c, "L"c, "L"c,

"O"c}

PrintArray(integerArray)

PrintArray(doubleArray)

PrintArray(charArray)

End Sub

Public Sub PrintArray(Of E)(ByVal inputArray() As E)

For Each element As E In inputArray


Next element

184


End Sub

End Module

'WithEvents and Event method


Shared WithEvents Click3 As New TripleClicker


Click3.Click()

Click3.Click()

Click3.Click()

End Sub

Private Shared Sub Click3_TplClick(ByVal Text As String)

Handles Click3.TplClick


End Sub

End Class

Public Class TripleClicker

Public Event TplClick(ByVal Text As String)

Public Sub Click()

Static intCount As Integer = 0

intCount += 1

If intCount >= 3 Then

intCount = 0

RaiseEvent TplClick("The button was triple

clicked.")

End If

End Sub

End Class

'File Creation, Last Write and Last Access time

185

Imports System.IO



Console.WriteLine(File.GetCreationTime("test.vb"))

Console.WriteLine(File.GetLastWriteTime("test.vb"))

Console.WriteLine(File.GetLastAccessTime("test.vb"))

End Sub

End Class

'File Exists

Imports System.IO



Console.WriteLine(File.Exists("test.vb"))

End Sub

End Class

'File's Attributes

Option Strict On

Imports System.IO

Public Module FileSystemAttributes

Public Sub Main()

Dim docPath As String =

My.Computer.FileSystem.SpecialDirectories.MyDocuments

186

For Each fn As String In

My.Computer.FileSystem.GetFiles(docPath)

Dim fi As FileInfo = New FileInfo(fn)

Console.WriteLine("{0}: {1}", fi.Name,

fi.Attributes.ToString())

Next

End Sub

End Module

'FileAttributes



Dim lngAttributes As Long

lngAttributes =

System.IO.File.GetAttributes("test.txt")

' Use a binary AND to extract the specific attributes.

Console.WriteLine("Normal: " & CBool(lngAttributes And

IO.FileAttributes.Normal))

Console.WriteLine("Hidden: " & CBool(lngAttributes And

IO.FileAttributes.Hidden))

Console.WriteLine("ReadOnly: " & CBool(lngAttributes

And IO.FileAttributes.ReadOnly))

Console.WriteLine("System: " & CBool(lngAttributes And

IO.FileAttributes.System))

Console.WriteLine("Temporary File: " &

CBool(lngAttributes And IO.FileAttributes.Temporary))

Console.WriteLine("Archive: " & CBool(lngAttributes

And IO.FileAttributes.Archive))

End Sub

End Class

187

'Copy a file

Imports System.IO

Imports System.Text



Dim mySourceFileStream As FileStream

Dim myDestFileStream As FileStream

Dim bteRead() As Byte

Dim intByte As Integer

Dim bteMessage(128) As Byte

Dim strCopyMessage As String = ""

Try

myDestFileStream = New FileStream("dest.txt",

FileMode.OpenOrCreate, FileAccess.Write)

bteMessage =

Encoding.ASCII.GetBytes(strCopyMessage)

myDestFileStream.Write(bteMessage, 0,

bteMessage.Length)

mySourceFileStream = New FileStream("source.txt",

FileMode.OpenOrCreate, FileAccess.Read)

intByte = mySourceFileStream.Length

ReDim bteRead(intByte)

mySourceFileStream.Read(bteRead, 0, intByte)

myDestFileStream.Write(bteRead, 0, intByte)

myDestFileStream.Close()

mySourceFileStream.Close()

Catch ex As IOException


End Try

End Sub

End Class

'Delete a file with kill

188



Kill("Test.csv")

End Sub

End Class

'Delete a file

Imports System.IO



Dim f6 As File

f6.Delete("test.txt")

End Sub

End Class

'Move a file with File.Move

Imports System.IO



Dim f35 As File

File.Move("test.txt", "text2.txt")

End Sub

End Class

'Use FreeFile

Option Strict On

189

Public Module Checking

Private Const filename As String = "CheckFile.dat"

Public Sub Main()

Dim fn As Integer = FreeFile

Dim fileOpened As Boolean

Try

FileOpen(fn, filename, OpenMode.Append)

fileOpened = True

WriteLine(fn, 1605, Date.Now, "Books", 2.19)

Catch e As Exception

Console.WriteLine(e.GetType().Name & ": " &

e.Message)

Finally

If fileOpened Then FileClose(fn)

End Try

End Sub

End Module

'FileMode.OpenOrCreate

Imports System.IO



Dim fs As System.IO.FileStream

Dim w As System.IO.BinaryWriter

Dim buffer As String

Dim c As Char

c = Chr(9)

fs = New System.IO.FileStream("test.txt",

IO.FileMode.OpenOrCreate)

w = New System.IO.BinaryWriter(fs)

w.Seek(0, System.IO.SeekOrigin.Begin)

w.Write("writing data via BinaryWriter")

w.Close()

fs.Close()

End Sub

End Class

190

'FileMode.Open with FileAccess.Read

Imports System.IO



Dim f As System.IO.FileStream

Dim r As System.IO.StreamReader

Dim mylength As Integer

Dim i As Integer

f = New System.IO.FileStream("test.txt",

IO.FileMode.Open, IO.FileAccess.Read)

r = New System.IO.StreamReader(f)

Console.WriteLine(r.ReadToEnd())

f.Close()

r.Close()

End Sub

End Class

'Path.GetInvalidPathChars

Imports System.IO



For Each ch As Char In Path.GetInvalidPathChars()

Console.WriteLine(ch)

Next ch

End Sub

End Class

'Path.GetInvalidFileNameChars

191

Imports System.IO



For Each ch As Char In Path.GetInvalidFileNameChars()

Console.WriteLine(ch)

Next ch

End Sub

End Class