PRB: SetFocus During Form Load May Cause Illegal Function Call

Retired KB Content Disclaimer

View products that this article applies to.

This article was previously published under Q88477

SUMMARY

Symptoms

Using the SetFocus method to set the focus to a specific control on a form during the form load event procedure may result in an "Illegal Function Call" error.

Back to the top

Cause

This error occurs because the form that the control is on is not yet visible.

Back to the top

Resolution

To prevent this error from occurring, execute Form.Show before executing the SetFocus method.

Back to the top

MORE INFORMATION

Steps to Reproduce Problem

Start Visual Basic or from the File menu, choose New Project (ALT, F, N) if Visual Basic is already running. Form1 is created by default.
Place a text box (Text1) on Form1.

Add the following code to the Form_Load procedure for Form1:

   Sub Form_Load ()
      Text1.SetFocus
   End Sub

Press F5 to run the application. The line of code in the load event will be highlighted with the error "Illegal Function Call."

If you show the form before executing SetFocus, the program will run as expected.

   Sub Form_Load ()
      Form1.Show
      Text1.SetFocus
   End Sub

Back to the top

APPLIES TO

Microsoft Visual Basic 2.0 Standard Edition
Microsoft Visual Basic 3.0 Professional Edition
Microsoft Visual Basic 2.0 Professional Edition
Microsoft Visual Basic 1.0 Standard Edition

Back to the top

kbprb KB88477

Back to the top

Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

Back to the top