Re: Updating progress bar after OnInitDialog

David Wilkinson <>
Thu, 12 Jun 2008 06:31:25 -0400
Giovanni Dicanio wrote:

Hi all,

I have a dialog-box: when the user presses a button, I would like to show a
new modal dialog-box with a progress bar indicating some potentially lengthy
operation progress. This operation is done by a worker thread.
(The worker thread sends messages to the GUI thread, to update progress bar

The problem is that I can't start the thread or send messages to the
progress bar from OnInitDialog. So, I thought about this "work-around": in
OnInitDialog, I create a timer (just 200 ms), and return.
When the timer "ticks" for the first time (i.e. after 200 ms since
OnInitDialog returned), the OnTimer handler calls another member function of
the dialog-box. This member function starts the worker thread, which can now
send messages to GUI thread to update the progress bar (in fact, after
OnInitDialog, the progress bar is ready to process messages).
(KillTimer is immediately called to avoid new firing of timer events.)

Everything is working fine.

I just would like to know if there is any different solution to that
problem, instead of using a one-shot timer to postpone beginning of work
after OnInitDialog.


I'm sure I'm missing something, but why can you not "start the thread or send
messages to the progress bar from OnInitDialog"?

One-shot timer is a common technique for delaying some operation until after the
dialog is displayed. Another is to use a custom PostMessage(). But if you are
starting a thread, I don't see why you need it, because AfxMessageBox() return

Is this because you have two layers of modal dialogs?

David Wilkinson
Visual C++ MVP

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