asked on

Testing for the existence of an ActiveControl

If you use aForm.ActiveControl or Screen.ActiveControl when there isn't one, an error occurs. How do test for the presence of an active control before trying to refer to it?

Markus Fischer

Hello,

The standard answer for that is "use error management", I guess:

Sub TestThis()

Dim ctl As Control

On Error Goto TestThis_Error

Set ctl = Screen.ActiveControl

' [...]

TestThis_Exit:

Exit Sub

TestThis_Error:

If Err.Num = <insert number here> Then
' take propert action, e.g.
Resume TestThis_Exit
ElseIf Err.Num = ....
' ...
End If
MsgBox Err.Description, , "Error " & Err.Num
Resume TestThis_Exit

End Sub

You code should have this anyway ;)

Cheers!
(°v°)

ASKER CERTIFIED SOLUTION

Markus Fischer

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

xerle

ASKER

Harfang,

I modified your last suggestion a little as follows:

Function ActiveControlExists(aForm As Form) As Boolean

'Test for the existence of a valid ActiveControl.

On Error GoTo HandleErr

Dim aControl As Control
Set aControl = aForm.ActiveControl
ActiveControlExists = True

Exit Function

HandleErr:
ActiveControlExists = False

End Function

Thanks,
Erle

Markus Fischer

Sure, looks good. ;)

Probably not important, but an error handler should end with either a Resume. clearing of the error, or raising a new one...

HandleErr:
ActiveControlExists = False
Err.Clear ' <--- added

End Function

But again, I'm not sure this makes any difference...

Happy programming!
(°v°)