Re: ATL ActiveX in C# User Control crashing designer

"Alexander Nickolov" <>
Mon, 14 May 2007 14:37:36 -0700
Some issue with the designer I expect. The control shouldn't get
UI activated in design mode.

You may want to post this in some .NET group as well. Consider


Though I'm not sure that't really the right group to go for your
question, the folks there might be better able to direct you...

Alexander Nickolov
Microsoft MVP [VC], MCSD

"jhamers" <> wrote in message


I'm using a ATL ActiveX on a C# windows form (Visual studio 2005).
That works great. However, I wanted to create a C# user control which
would wrap this ActiveX. Therefor I created an empty user control and
just put this ActiveX on it. No problem so far.

However, when I wanted to test this dummy User Control, I put this
user control on its turn on a c# form.
That's when it started to go wrong. Once it is put on the form, I can
not move it anymore and when I click in the user control I get an
error saying that an unhandled exception caused the designer to crash.
In the activex there is a stack trace displayed:
at ...AxHost.UiDeactivate

I hooked up an instance of Visual studio 2003 to debug the Visual
studio 2005.
And it seems it is going wrong in the
::SetFocus call in SetControlFocus(TRUE) which is called from
CComControlBase::InPlaceActivate(LONG iVerb, const RECT* /
*prcPosRect*/) in atlctl.h

Anybody any ideas why an activex is making the designer go bananas
like this? And how to prevent it?

Kind Regards,

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