Re: ActiveX control blocking the GUI

From:

"Scott McPhillips [MVP]" <org-dot-mvps-at-scottmcp>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 27 Jul 2006 10:55:33 -0400

Message-ID:

<uQy#vyYsGHA.452@TK2MSFTNGP05.phx.gbl>

mbilic_2000@yahoo.com wrote:

This method is a long lasting blocking method, and since its called
from a buttom message handler, the dialog's message dispatcher gets
blocked and the entire application becomes unresponsive.

My question: is there a way in MFC to circumvent this issue?

I tried one simple and vey dirty (naive) way to solve this by creating
a worker thread from the button's message handler, passing the thread a
pointer to this ActiveX control's object (an instance of MFC-generated
wrapper class) and then calling the objects method from the thread. The
result was miserable ofcourse, the application crashed with an access
violation exception somwhere in MSVBVM60.

The best fix would be to change the ActiveX control so it does not
block. If that is not possible then you could try putting both the
control creation and calls into a user-interface thread (not worker
thread). It may even be necessary to create a child dialog in the
thread so that the parent of the ActiveX control will be in the same
thread as the control. You have to get everything that the control
interacts with into the secondary thread.

--
Scott McPhillips [VC++ MVP]