PRB: Programmatically Changing Focus Does Not Cause Validation

Code that changes the value of a TextBox or of another control, and then moves the focus to another control where the CausesValidation property is True does not fire the Validate events of the changed control.

This behavior occurs because changing the focus with code does not trigger Validate event.

To resolve this behavior, call the ValidateControls method when you change values and focus by the use of code.

This behavior is by design.

By design, if you change the values of controls in code, you must explicitly call ValidateControls to run the Validate events. Validate does not run automatically in this scenario. Similarly, if you close the form after you edit a control without leaving that control, the Validate event does not fire because it does not lose focus. In this case, you can use the QueryUnload event of the Form to decide if ValidateControls should be called.

Steps to Reproduce the Behavior

1. Open a new Standard EXE project in Visual Basic 6.0; Form1 is created by default.
2. Add the CommandButton control, Command1, and two TextBox controls, Text1 and Text2, to Form1. CausesValidation is True by default.
3. Add the following code to the General Declarations section of Form1:

   Private Sub Command1_Click()
       Dim i As Integer
       
       For i = 0 To Controls.Count - 1
           If TypeOf Controls(i) Is TextBox Then
              Controls(i).SetFocus
              Controls(i).Text = "Hello! " & i
           End If
       Next i
   End Sub
   
   Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
       If UnloadMode = vbFormControlMenu Then
   '        Me.ValidateControls
       End If
   End Sub
   
   Private Sub Command1_GotFocus()
       Debug.Print "Command1 got focus"
   End Sub
   
   Private Sub Text1_GotFocus()
       Debug.Print "Text1 got focus"
   End Sub
   
   Private Sub Text1_Validate(Cancel As Boolean)
       Debug.Print "Text1 validate"
   End Sub
   
   Private Sub Text2_GotFocus()
       Debug.Print "Text2 got focus"
   End Sub
   
   Private Sub Text2_Validate(Cancel As Boolean)
       Debug.Print "Text2 validate"
   End Sub
   						

4. Press F5 to run the project. Click Command1 and notice the Validate events for the TextBox controls do not fire.
5. Edit the contents of Text2 and then close the form. The Validate event is not fired for Text2.
6. Uncomment the ValidateControls line in the Form_QueryUnload event, run the project, and then repeat step 5; the Validate event fires.

For additional information about Validate and CausesValidation, click the article numbers below to view the articles in the Microsoft Knowledge Base: