INTRODUCTION CHAPTER #1

Visual Basic .NET

VB.Net General features

It is an object oriented language In the past VB had objects but focus was not placed on

them VB. Net use objects and inheritance with everything

Uses exception handling extensively Like with most OOP languages, exceptions that are not

handled will cause programs to abnormally end or exitUses “generics” with creating classes and Sub

programsProvides a quick way to develop heavy duty

applications in a windowing environmentIt is a useful tool for developing event driven

programs Can create both windows applications and web

applications at the click of a mouse button

VB.Net General features

The interface between the Databases and applications Are the same between web apps and windows apps All data are transferred between the apps in XML format

regardless if it is a web application or a windows application A copy of the data from the database is loaded into a data set. Persistent connections between the application and the database

no longer exists Every form is a class and new forms now have to be

instantiated VB .Net is still not case sensitive

Data Types in VB .NET

Data Types and possible values Integer -> (4 bytes) Double -> floating point numbers with 14 digits of accuracy (8

Bytes) Decimal -> decimal values ( 16 bytes replaced currency in 6.0) Date -> the date (8 Bytes) Byte -> 0 to 255 (1 Byte) Char -> Unicode character (2 Bytes) Boolean ->True or false value (2 Bytes) Single -> floating point number with 6 digits of accuracy (4 bytes) Short -> 2 byte integer Long -> 8 byte integer String -> an arrangement of alpha-numeric characters varies in

length Object -> any data type 4 bytes

Functions and Sub procedures / Programs in VB .NET (Methods)

Functions and sub procedures must either have a sub or function keyword in the function or sub procedure heading

They can be either public or private (following the same conventions in OOP languages such as C++ or Java)

All parameters are passed by value by default in VB .NET

Parameters of any data type may be passed by referenceAll Objects and arrays are passed by reference not valueAll events are handled by a sub procedure in VB .NETFunctions return a value and Sub Procedures do Not

The .NET Framework

Primarily a development platform (mostly effects application development)

Consists of two main parts Common Language Runtime .NET Framework Class Library

CLR (Common Language Runtime)

CLR works like a virtual machine in executing all languages. All .NET languages must obey the rules and standards imposed by CLR. Examples: Object declaration, creation and use Data types, language libraries Error and exception handling Interactive Development Environment (IDE)

Development Mixed language applications

Common Language Specification (CLS) Common Type System (CTS) Standard class framework Automatic memory management

Consistent error handling and safer execution

Compilation of .NET code

All .NET languages are first compiled into an intermediate language called MSIL or IL (Microsoft Intermediate Language)

The MSIL is then “Just In Time” (JIT) compiled at first execution of the code and managed by the CLR

All MSIL or IL code can be compiled directly to native code with the following Compiling native code will provide faster startup execution

of the code Performance during execution of the code will then be

sacrificed During JIT Optimization is placed on the Managed Code in

order to improve performance at the time of execution

.Net Framework Class Library

Provide a library of base classes that developers can use in their own applications written in ANY .Net language

Because of the use of these base classes, Inheritance can then be extensively used in languages that use the .Net Framework

.Net applications can be written by any or a combination of many .Net languages

Languages include VB .Net C# J# Visual C++ (default in studio is set for managed C++)

Framework, Languages, And Tools

Base Class Library

Common Language Specification

Common Language Runtime

ADO.NET: Data and XML

VB VC++ VC#V

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and Web Forms

JScript …

WindowsForms