microsoft visual basic 2008 chapter three program design and coding

Microsoft Visual Basic 2008

CHAPTER THREE

Program Design and Coding

3

Chapter 3: Program Design and Coding 2

Objectives

►Change the BackColor property of an object

►Add images to a PictureBox object

►Locate and save an image from the World Wide Web

►Import an image into the Program Resources folder

►Size an image

3


Objectives

►Set the Visible property in the Properties window

►Set the Enabled property in the Properties window

►Run a Visual Basic 2008 program

►Enter Visual Basic 2008 code

►Understand Visual Basic 2005 code statement formats

3


Objectives

►Use IntelliSense to enter Visual Basic 2008 code

statements

►Using code, set the Visible property of an object

►Using code, set the Enabled property of an object

►Enter comments in Visual Basic 2008 code

3


Objectives

►Correct errors in Visual Basic 2008 code

►Write code to use the Close( ) procedure

►Print code

►Prepare an Event Planning Document

3


Event Planning Document

3


Phase 4 – Code the Program

►After the events and tasks within the events have been identified, the developer is ready to code the program

►The developer enters the code (Visual Basic statements) and implements the logic

3


BackColor Property [form]

►Click the Windows Form object to select it

►If necessary, scroll in the Properties window until the

BackColor property is displayed, and then click the right

column of the BackColor property

►Click the BackColor arrow. Then, if necessary, click the

Web tab to display the Web tabbed page

►Scroll until the Cornsilk color is displayed in the list of

colors

►Click Cornsilk on the color list

3


BackColor Property

3


Locating and Saving an Image from the World Wide Web

►Open your Internet browser. Then, enter scsite.com/vb2008/ch3/images in the Address box and press the ENTER key

►Locate the StandardRoom.jpg image and then right-click the image

►Click Save Picture As on the shortcut menu►Identify the drive and folder where the image will be

stored. Enter the image file name, StandardRoom, in the File name text box

►Click the Save button in the Save Picture dialog box to save the image in the selected location

3


Locating and Saving an Image from the World Wide Web

3


Importing the Image into the Program Resources Folder

►With Visual Studio 2008 and the Hotel Room Selection Visual Basic program open, select the picStandardRoom PictureBox object by clicking it.

Scroll in the PictureBox Properties window until the Image property is visible. Click the Image property name in the left list in the Properties window

►Click the Ellipsis button in the right column of the Image property

►Click the Import button in the Select Resource dialog box. Then, using the features of the Open dialog box, locate the file you want to import into the program

3


Importing the Image into the Program Resources Folder

►Click the Open button in the Open dialog box

►With the StandardRoom file name selected in the Project resource file list, click the OK button in the Select Resource dialog box

3


Sizing an Image

►With the PictureBox object containing the StandardRoom image selected, scroll in the picStandardRoom Properties window until you see the SizeMode property. Click the SizeMode property name in the left column and then click the SizeMode arrow in the right column of the SizeMode property

►Click StretchImage in the SizeMode list

3


Sizing an Image

3


Visible Property

►If necessary, select the picStandardRoom PictureBox object.

►Scroll in the Properties window until the Visible property is displayed.

►Click the Visible property name in the left column, and then click the Visible arrow in the right column of the Visible property

►Click False on the Visible property list

3


Visible Property

3


Enabled Property

►Select the btnSelectRoom object. ►Scroll in the Properties window until the Enabled

property is displayed. ►Click the Enabled property name in the left column,

and then click the Enabled arrow in the right column of the Enabled property

►Click False on the Enabled property list

3


Enabled Property

3


Running a Program

►Click the Start Debugging button on the Standard toolbar

3 Running a Program


3


Entering Visual Basic Code for Event Handling

►With Visual Studio 2008 and the Hotel Room Selection program open and the frmHotelRoomSelection.vb [Design] tabbed window visible

►point to the Standard Room Button object in the Windows Form object

►Double-click the Standard Room Button object

3


Entering Visual Basic Code for Event Handling

3


Visual Basic 2008 Coding Statements

►The Visual Basic syntax specifies how each statement must be written

►When the user clicks the Standard Room button while the program is running, the standard room image should be displayed in the picStandardRoom PictureBox object

3


General Format of a Visual Basic Statement

3


IntelliSense

►IntelliSense displays all allowable entries you can make in a Visual Basic statement each time a dot, equal sign, or other special character required for the statement is typed

►You must use the word, Me, followed by a dot before the name of the object, to take full advantage of IntelliSense

3


Entering a Visual Basic Statement

►With the code window open and the insertion point positioned as shown in Figure 3-25 on page 131, type me followed by a period

►To identify the correct entry, type the first letters of the entry until the entry is selected. In this case, type pics on your keyboard.

►When IntelliSense highlights the correct object name, press the key on the keyboard corresponding to the entry that is to follow the object name. In this case, press the PERIOD key

►As with the object name in the second step, the next step is to enter one or more characters until IntelliSense highlights the desired property in the list. Type the letter, v on your keyboard

3



►Press the key for the character that is to follow the property name. In this case, press the SPACEBAR on the keyboard

►Press the EQUAL SIGN key on the keyboard and then press the SPACEBAR

►Type t on the keyboard

►Press the key for the character that is to follow the True entry. In this case, press the ENTER key

3



3


Setting the Visible Property to False

►With the insertion point on the second line of the coding window for the click event of the Standard Room button, type me. on your keyboard

►Type picd to highlight the picDeluxeRoom entry in the IntelliSense list

►Press the key on the keyboard for the character that is to follow the object name. In this case, press the PERIOD key

►Press the SPACEBAR, press the EQUAL SIGN key, and then press the SPACEBAR

►Type f and then press the ENTER key

3


Setting the Visible Property to False

3


Enabled Property

►Type me. to display the IntelliSense list►Type btnse until IntelliSense highlights the

btnSelectRoom entry in the list►Type a period, type e, press the SPACEBAR, press the

EQUAL SIGN key, press the SPACEBAR again, and then type t to select True in the IntelliSense list

►Press the ENTER key to enter the completed statement and place the insertion point on the next line

3


Enabled Property

3


Comments in Program Statements

►To insert a blank line following the event code generated by Visual Studio that begins with the word, Private, click anywhere in that line and then press the END key on your keyboard

►Press the ENTER key

►Type the first line of the comments, beginning with an apostrophe, as shown in Figure 3-46 on page 143, and then press the ENTER key

3


Comments in Program Statements

3


Same Line Comments

3


Introductory Comments

►Click to the left of the word, Public, on line 1 in the program to place the insertion point on that line

►Press the ENTER key one time, and then press the UP ARROW key one time

►Type an apostrophe, a space, the text, Program Name: and then press the TAB key one time

►Type Hotel Room Selection as the name of the program. Then, press the ENTER key

3


Introductory Comments

3


Correcting Errors in Code

►Using IntelliSense reduces the likelihood of coding errors considerably, although it is still possible to code an error

• One possible error may be forgetting an apostrophe in a comment statement

►A build errors message means the Visual Basic compiler detected a coding error in the program

3 Correcting Errors in Code


3



►Click the No button in the Microsoft Visual Studio dialog box that informs you of a build error

►Double-click anywhere on the error line

►Click in the leftmost column on line 7 to place the insertion point at that location

►Type an apostrophe

►Click anywhere in the code editing window

3



3


Additional Click Events

►On the frmHotelRoomSelection.vb [Design] tabbed page, double-click the Exit Window Button object

3


Close Procedure

►With the insertion point positioned as shown in Figure 3-64 on page 154, type me. to display the IntelliSense list. Type cl to highlight Close in the IntelliSense list

►Press the ENTER key

3


Printing Code

►Click File on the menu bar to display the File menu►Click Print on the File menu to display the Print dialog

box.►Ensure that a check mark appears in the Include line

numbers check box if you want line numbers on your printout. Most developers prefer line numbers on printouts

►Make any other selections you find necessary in the Print dialog box.

►Click the OK button in the Print dialog box to print the code

3


Event Planning Document

3


Summary

►Prepare an Event Planning Document

►BackColor property

►Images / PictureBox object►Images from the World Wide Web►Program Resources folder►Size an image

3


Summary

►Visible property►Enabled property

►Run a Visual Basic 2008 program►Enter Visual Basic 2008 code

►Understand Visual Basic 2008 code statement formats

3


Summary

►IntelliSense

►Comments in Visual Basic 2008 code►Correct errors in Visual Basic 2008 code

►Close() procedure

►Print code

Microsoft Visual Basic 2008

CHAPTER THREE COMPLETE

Program Design and Coding

microsoft visual basic 2008 chapter three program design and coding

Documents