Re: create window before calling CDialog::DoModal()?

From:
"David Ching" <dc@remove-this.dcsoft.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Sun, 01 Jul 2007 00:38:01 GMT
Message-ID:
<JHChi.27584$YL5.2090@newssvr29.news.prodigy.net>
"Frank Cusack" <fcusack@fcusack.com> wrote in message
news:m2myyhus69.fsf@sucksless.local...

This is a tray app, and as such the main window / main GUI thread is
always running (I guess), ie it does not block. So I can receive
multiple events even with a modal dialog. That is, even though I'm
blocked in DoModal(), I can receive another event which tries to
invoke the same dialog box.

I guess I could disable the appropriate popup menu item, but it's
nicer to bring the currently active dialog for the menu item to the
foreground.


I had the same issue several years ago, and I believe I recently read in
OldNewThing (Raymond Chen), the proper way of avoiding this problem is to
make sure you create your dialog with the parent window of your main window,
e.g.

void CMyMainWindow::OnAbout()
{
    CAboutDlg dlg(this); // <--- the parent window of About dialog is
CMyMainWindow, which also is owner of tray icon
    dlg.DoModal();
}

I assume your code to popup the tray icon menu is something like:

  // Display the menu at the current mouse location. There's a "bug"
  // (Microsoft calls it a feature) in Windows 95 that requires calling
  // SetForegroundWindow. To find out more, search for Q135788 in MSDN.
  //
  CPoint mouse;
  GetCursorPos(&mouse);
  ::SetForegroundWindow(m_nid.hWnd); // <-- brings CMyMainWindow to
foreground, along with modal AboutDlg showing
  ::TrackPopupMenu (pSubMenu->m_hMenu, TPM_LEFTBUTTON | TPM_RIGHTBUTTON,
mouse.x, mouse.y, 0,
        m_nid.hWnd, NULL);
  ::PostMessage(m_nid.hWnd, WM_NULL, 0, 0);

So now if the About Dialog is showing, when the tray icon is right-clicked
and the above code shows the popup menu, the SetForegroundWindow(m_nid.hWnd)
brings both the CMyMainWindow to the foreground, as well as the CAboutDlg
(due to CMyMainWindow being its parent).

I have not enhanced my code with this, so haven't tried it, but perhaps it
would solve your problem.

If not, then it seems something simple like adding a flag to not show the
AboutDlg twice could be used:

void CMyMainWindow::OnAbout()
{
    if ( !m_bAboutDlgShowing ) // declared as BOOL
CMyMainWindow::m_bAboutDlgShowing
    {
        m_bAboutDlgShowing = TRUE;

        CAboutDlg dlg(this); // <--- the parent window of About dialog is
CMyMainWindow, which also is owner of tray icon
        dlg.DoModal();

        m_bAboutDlgShowing = FALSE;
     }
}

-- David

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