IPogressDialog

I am using an IProgressDialog object to reflect the progress during a long operation. Through experimentation, I've noticed that the Cancel button is not responsive if I pass a non-NULL handle as the parent to the progress dialog. And, if I try to move the dialog, it will not work. It doesn't matter if I use a marquee style or a stepped style. Here's some sample code...

Code:

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UIProgressDialog ProgressDlg;

ProgressDlg.Init ();
ProgressDlg.SetTitle (_T("Sample Title"));
//xxxProgressDlg.StartProgressDialog (m_hWnd, UIProgressStyle::UIPS_Marquee);
ProgressDlg.StartProgressDialog (m_hWnd);
ProgressDlg.SetCancelMessage (_T("Cancelling..."));
ProgressDlg.SetLineText (1, _T("Line 1 of text"), FALSE);
ProgressDlg.SetLineText (2, _T("Line 2 of text"), FALSE);
ProgressDlg.SetLineText (3, _T("Line 3 of text"), FALSE);

for (int i=0; i<1000; i++)
        {
                CString msg;
                        if (ProgressDlg.HasUserCancelled()) break;
                msg.Format ("I'm processing item %d", i);
                ProgressDlg.SetLineText (2, msg, FALSE);
                Sleep(50);
                ProgressDlg.SetProgress(i, 1000);
        }

ProgressDlg.StopProgressDialog ();

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Is this by design? Is this a bug? Am I redirecting the progress dialog messaging by providing a handle to a parent dialog? The only way I can get it to work correctly, is to pass a NULL handle.

Never used this specific UIProgressDialog, but I am guessing you have to manually pump the messages through when you have the parent specified. In this case you need to call a function like the one below from inside your loop.

Code:

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void CMainFrame::DoEvents() {
        MSG msg;

        // Process existing messages in the application's message queue.
        // When the queue is empty, do clean up and return.
        while (::PeekMessage(&msg,NULL,0,0,PM_NOREMOVE) && !g_bCancel)
        {
                if (!AfxGetThread()->PumpMessage())
                        return;
        }
}

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Thanks for the reply. However, I don't think your sample is applicable here. IProgressDialog creates a separate thread to do its work. And, there is no mention in the documentation that using a non-NULL handle for a parent requires handling the message processing differently.