FIX: ActiveControl Property of Screen Object Loses Memory

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This article was previously published under Q113031

SYMPTOMS

It is possible to receive an "Out of Memory" error when using the ActiveControl property of the Visual Basic Screen object.

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CAUSE

The ActiveControl property of the screen object can leak memory when used with the Is operator.

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RESOLUTION

Use a temporary variable to work around the problem. For example, change the command click event in the code listed in the More Information section below to this code:

Sub Command1_Click ()
   Dim ctr As Long
   Dim ActControl As control
   Do
      ctr = ctr + 1
      Text1.Text = ctr
      ' Use a temporary object variable
      Set ActControl = Screen.ActiveControl
      If ActControl Is Command1 Then
      End If
   Loop
End Sub

This code should run indefinitely.

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STATUS

Microsoft has confirmed this to be a bug in Visual Basic version 3.0 for Windows. This problem has been corrected in Visual Basic version 4.0.

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MORE INFORMATION

Steps to Reproduce Problem

Start a new project in Visual Basic. Form1 is created by default.
Put a command button (Command1) and a text box (Text1) on the form.

Add the following code to the command button's click event:

   Sub Command1_Click ()
      Dim ctr As Long
      Do
         ctr = ctr + 1
         Text1.Text = ctr
         If Screen.ActiveControl Is Command1 Then
         End If
      Loop
   End Sub

Run the program, and you will receive an "Out of Memory" error eventually.

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APPLIES TO

Microsoft Visual Basic 3.0 Professional Edition

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kbbug kbfix KB113031

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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.

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