1. PictureBox, MessageBox, Multiple Forms, Splash Screens and Timers
Chapter 2 pp
Chapter 4 pp
Chapter 7 pp
Chapter 8 pp
Chapter 2

2. Chapter 2
PictureBox Control
Chapter 2

3. PictureBox Control Download these bmp files from the ftp site:
Oklahoma.bmp
Utah.bmp
Insert PictureBox controls and name them:
picOklahoma
picUtah
Adjust SizeMode.
Chapter 2

4. Picture Box SixeMode Values
AutoSize
Adjusts automatically to fit size of image it displays.
CenterImage
Centers image within control size when bounding box is > than the image.
Displays center portion of image and cropped to fit if box is < than image.
Normal
Aligns image with upper left corner of control box; clips image if image is larger than box size.
StretchImage
Scales image to fit within control box. Stretches smaller image or shrinks larger image.
Chapter 2

5. Chapter 2

6. Chapter 4
MessageBox Method
Chapter 2

7. MessageBox Dialog box that displays a message to the user.
Types of messages:
Information (Your data has been added)
Warnings (Do you want to save?)
Critical (System Error)
Question (Need input from user)
Chapter 2

8. MessageBox.Show Method
MessageBox.Show("Message")
Message box with OK button; no title
Chapter 2

9. MessageBox("Message","Caption")
Comma separates arguments.
Quotes surround string literals.
Underscore provides line continuation.
Caption appears on title bar.
Chapter 2

10. MessageBox("Message","Caption",Buttons)
MessageBoxButtons.AbortRetryIgnore
MessageBoxButtons.OK
MessageBoxButtons.OKCancel
MessageBoxButtons.RetryCancel
MessageBoxButtons.YesNo
MessageBoxButtons.YesNoCancel
Will program later when we can control action of buttons.
Chapter 2

11. MessageBox.Show("Message","Caption",Buttons,Icon)
MessageBoxIcon.Information
MessageBoxIcon.Asterisk
MessageBoxIcon.Error
MessageBoxIcon.Stop
MessageBoxIcon.Warning
MessageBoxIcon.Exclamation
MessageBoxIcon.Question
Chapter 2

12. MessageBox Example
Chapter 2

13. Which button clicked? Will cover later after learning about variables.
Stay tuned…
Chapter 2

14. Multiple Lines: ControlChars.CrLf
Displays multiple lines within a message box.
ControlChars.CrLf
Carriage return/line feed
Begin a new line
Example
MessageBox.Show("This is line 1" & _ ("This is line 2")
Chapter 2

15. Chapter 7
Multiple Forms
Chapter 2

16. Form Names and File Names
Default Name Property: Form1
Default File Name: Form1.vb
Should assign descriptive form names for multiple-form programs
Need to do more than change Name property:
Also change file name
Also change Startup Object
Chapter 2

17. Default File Name and Name
Chapter 2

18. Changed File Name and Name
Must keep .vb filename extension.
Chapter 2

19. Startup Object (p. 405)
Right-click Project name (in Solution Explorer window) and choose Properties. …or…
Choose Project, Properties.
Chapter 2

20. Startup Object
Click Startup object drop-down arrow and choose form name to be first object (form) that appears.
Chapter 2

21. Add Form Click Add New Item on toolbar. Keep the .vb extension
Chapter 2

22. Switching Between Forms
Active Form
Code window
for frmStates form
frmstates form
Chapter 2

23. Instance of Form 1st step to display form: create an instance.
Dim ObjectVariable As New ClassName()
ObjectVariable
Name that refers to instance of form, sort of like an alias (not name of form itself though)
Holds memory address of object (form) so that you can use it
ClassName()
Form’s class name—the name used in the Name property for a form
Chapter 2

24. Example Dim errorForm As New frmError()
errorForm is object variable name that creates instance of actual form
frmError is the name of the actual form
Does not actually display form
Chapter 2

25. ShowDialog Method Modal method ObjectVariable.ShowDialog()
No other form can receive focus until the modal form is closed.
Forces user (or timer) to acknowledge active form
ObjectVariable.ShowDialog()
errorForm.ShowDialog()
Chapter 2

26. Show Method Modeless form ObjectVariable.Show() errorForm.Show()
Allows user to switch focus to another form while the modeless form is displayed
ObjectVariable.Show()
errorForm.Show()
Chapter 2

27. Close Method Closes a form and releases it from memory. Me.Close()
Me—current instance of the form
Close—closes current instance
Use to close a form in a multiple-form program without terminating the application
Chapter 2

28. Hide Method Removes form from the screen.
Keeps form in memory; does not release it.
Acts like changing form’s Visible property to False.
Chapter 2

29. Splash Screens & Timer Control
Chapter 8
Splash Screens & Timer Control
Chapter 2

30. Splash Screen (p. 513) Form displayed while a program loads.
Typical content:
Logo
Copyright Date (©2004)
Program Name (e.g., Microsoft Word)
Program Version (e.g., 2003)
Disappears after short time
TopMost Property: True
Displays on top of other forms
Chapter 2

31. Timer Control (p. 511)
Enables a program to automatically execute code at regular time intervals.
Examples:
Perform animation
Unload a form (such as a splash screen) after a time delay
Conventional prefix
tmr
tmrSplashScreen
Responds to Tick events
Chapter 2

32. Timer Properties Interval Property Enabled Property
Set to value of 1 or greater
Each 1 = 1 millisecond (thousandth of a second);
1,000 milliseconds = 1 second
Error if set to 0
Enabled Property
Set to True
Chapter 2

33. Hide Splash Screen (p. 515 Step 7)
Me.Close () closes the current form
Chapter 2

34. Main Form (p. 515 Step 9) Set as the Startup Object.
Create object variable in Form Load.
Use variable to show other form.
Form variable
declared
Actual name of form
Name of actual form
Form variable
used to show actual form
Chapter 2