Re: Window won't update

From:

"Alex Blekhman" <tkfx.REMOVE@yahoo.com>

Newsgroups:

microsoft.public.vc.language

Date:

Thu, 2 Jul 2009 19:09:42 +0300

Message-ID:

<ubq1D#y#JHA.1740@TK2MSFTNGP02.phx.gbl>

"Dave Cullen" wrote:

I have a dialog based MFC application that controls an
automation process. There is a worker thread in the background
handling some machine interfaces. The main thread provides
status displays via static text boxes and UpdateData(FALSE).

Do you call UpdateData from the working thread? If yes, then don't
do this. It may introduce deadlocks and all kinds of strange
problems similar to what you're observing now. Instead post
application defined message from working thread to main (GUI)
thread and in response to this message perform all necessary GUI
updates.

I've interspersed calls RedrawWindow() at various points within
the main loop with no apparent improvement.

If you have GUI thread stalled while waiting on interthread call,
then it won't help.

Is there anything else I can do to insure the window updates the
display?

You should not interract with GUI elements from working thread.
Just post (rather than send) predefined windows message to a
window in GUI thread.

And why would popping up a messagebox make everything start
working?

Message box is a modal dialog, therefore it establishes its own
message loop. This message loop dispatches messages for the owner
window, as well. Apparently, it unblocks stalled call somehow. It
is difficult to tell without seeing in debugger.

HTH
Alex