Re: MDIGetActive not Working!! Help Required

From:
Ulrich Eckhardt <eckhardt@satorlaser.com>
Newsgroups:
microsoft.public.vc.language
Date:
Thu, 26 Jul 2007 11:51:39 +0200
Message-ID:
<ce7mn4-2un.ln1@satorlaser.homedns.org>
rishabh.saxena.iitd@gmail.com wrote:

I have created a Modeless Dialog Box using threads (CWinThread).


I think this was a mistake. Normally, you only handle the UI in the main
thread and then use modeless dialogs to get an additional window that
doesn't block other windows. The modeless window is still a childwindow (I
think) of the main window, so they are part of the same message routing
net.
Alternatively, you create a thread where you create another window (you
could have made it modal, too) which is then another top-level window, so
its message routing is independent from the main window.

If this modeless dialog is e.g. a progress window for a longer background
task, you can instead use a thread to execute that task and a periodic
SendMessage() to update the progress. Alternatively, you can use a timer to
update the progress.

The thread invokes a dialog box (derived from CDialog) which acts as
modeless. The thread is invoked through a menu handler in CMyView
class. Now in my dialog box that is invoked in Cwinthread derived
class , i want my doc or view data to be there. Now can u tell me how
can i do that.


When exchanging messages between threads, you should not use C++ CWnd
objects but SendMessage&Co. However, I strongly advise against multiple
threads for UI handling, rather use a modeless dialog like mentioned above.

I tried this but the execution terminates abnormally.


Where? Why? What does the debugger say?

CMDIChildWnd * pChild =
          ((CMDIFrameWnd*)(AfxGetApp()->m_pMainWnd))->MDIGetActive();


Well, you are dereferencing two pointers here, either of which could be
zero. At least ASSERT() or VERIFY() that they are valid.

Uli

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