Re: Dialog window won't update display

From:

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

Newsgroups:

microsoft.public.dotnet.languages.vc,microsoft.public.vc.language

Date:

Thu, 31 Dec 2009 10:07:38 -0500

Message-ID:

<OlZTCsiiKHA.2132@TK2MSFTNGP05.phx.gbl>

"Dave Cullen" <none@mail.com> wrote in message
news:OI$AmaiiKHA.2188@TK2MSFTNGP04.phx.gbl...

I have a dialog based MFC application (VS2005) 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). The worker thread does not write to the window.

Sometimes the window will not update the display. The process keeps
running, so I know both threads are working. Strangely, if I pop up a
standard MessageBox for operator yes/no input the window will update it's
display after the messagebox closes and continue to update normally from
that point on.

I've interspersed calls to RedrawWindow() at various points within the
main loop with no apparent improvement. Is there anything else I can do to
insure the window updates the display? And why would popping up a
messagebox make everything start working?

Thanks
drc

When you pop up a message box it runs a message loop, which lets other
messages through to your main application. If updates don't happen until
you display the message box that is an indication that your main application
is not running its message loop. You also mention your "main loop," which is
suspicious. If your main thread is in a loop then the design is wrong. It
should consist of message handling functions that always return promptly (to
the MFC message loop). Your displays cannot update while your main thread
code is looping.

--
Scott McPhillips [VC++ MVP]