1. Do Now: What are the three steps to writing a Visual Basic Program?
1. Create the interface
2. Write the code
3. Test data

2. 3.2 Visual Basic Events An Event Procedure Walkthrough
Properties and Event Procedures of the Form
The Header of an Event Procedure

3. Event An event is an action, such as the user clicking on a button
Usually, nothing happens in a Visual Basic program until the user does something and generates an event.
What happens is determined by statements.

4. controlName.property = setting
Code
A set of statements that carry out tasks
Sample Statements
txtBox.ForeColor = Color.Red
txtBox.Visible = True
txtBox.Text = “Hello World”
General Form:
controlName.property = setting

5. Structure of an Event Procedure
Private Sub objectName_event(..)Handles objectName.event
statements
End Sub
(...) is filled automatically with (ByVal sender As System.Object, ByVal e As System.EventArgs)
Header

6. Create the following Sample Form
txtFirst
txtSecond
btnRed

7. Create an Outline for an Event Procedure; i.e. header and End Sub
1. Double-click on a control or
2. Use the Class Name and Method
Name boxes.
(We primarily use the first
method.)

8. Double Click on txtFirst
Sample Form
Double Click on txtFirst
txtFirst
txtSecond
btnRed

9. Code for Walkthrough Public Class frmDemo
Private Sub txtFirst_TextChanged()Handles txtFirst.TextChanged
txtFirst.ForeColor = Color.Blue
End Sub
End Class

10. Automatically pops up to give the programmer help.
IntelliSense
Automatically pops up to give the programmer help.

11. Double-click on btnRed
Sample Form
Double-click on btnRed
txtFirst
txtSecond
btnRed

12. Code for Walkthrough Public Class frmDemo
Private Sub txtFirst_TextChanged()Handles txtFirst.TextChanged
txtFirst.ForeColor = Color.Blue
End Sub
Private Sub btnRed_Click(...)Handles btnRed.Click
txtFirst.ForeColor = Color.Red
End Class

13. Event Procedure txtFirst.Leave
Select txtFirst from Class Name box drop-down list.
Select Leave from Method Name box drop-down list.

14. Code for Walkthrough
Private Sub txtFirst_Leave(...) Handles txtFirst.Leave
txtFirst.ForeColor = Color.Black
End Sub
Private Sub txtFirst_TextChanged()Handles txtFirst.TextChanged
txtFirst.ForeColor = Color.Blue
Private Sub btnRed_Click(...) Handles btnRed.Click
txtFirst.ForeColor = Color.Red

15. Handling Multiple Events
Event procedure can be invoked by two events.
Private Sub Button_Click()Handles btnRed.Click, txtSecond.Leave
txtFirst.ForeColor = Color.Red
End Sub

16. JUST SOME NOTES  A font's
name, style, and size properties cannot be altered in code with statements of the
txtBox.Font.Name = "Courier New"
txtBox.Font.Bold = True
txtBox.Font.Size = 16
If you want to know the settings, you can display them using lines like these:
1stBox.Items.Add(txtBox.Font.Name)
1stBox.Items.Add(txtBox.Font.Bold)
1stBox.Items.Add(txtBox.Font.Size)

17. More Notes  The following won't work: frmDemo.Text = "Demonstration"
The form is referred to by the keyword Me.
Me.Text = "Demonstration"

18. 2 EXAMPLES:
The form contains four square buttons arranged in a rectangular array. Each button has the caption "Push Me." When the user clicks on a button, the button disappears and the other three become or remain visible.