Re: My app's window class

From:
"SteveR" <maxsrussellatremovethisembarqmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Tue, 20 May 2008 19:44:22 -0400
Message-ID:
<exAKpNtuIHA.2068@TK2MSFTNGP05.phx.gbl>
I'm fishing around for examples for how to register my CMainFrame class.
I'm looking at this right now:

 BOOL CSampleApp::InitInstance()
   {
   /********************************************************************/
    // If a previous instance of the application is already running,
    // then activate it and return FALSE from InitInstance to
    // end the execution of this instance.

    CWnd *pWndPrev;

    // Determine if another window with your class name exists...
    if (pWndPrev = CWnd::FindWindow(_T("WCE_MyNewClass"),NULL))
    {
        // Bring previous instance to the foreground
    pWndPrev->SetForegroundWindow();
    return FALSE;
    }
    WNDCLASS wndcls;

    memset(&wndcls, 0, sizeof(WNDCLASS)); // start with NULL defaults

    wndcls.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;
    wndcls.lpfnWndProc = ::DefWindowProc;
    wndcls.hInstance = AfxGetInstanceHandle();
    wndcls.hIcon = LoadIcon(IDR_MAINFRAME); // or load a different icon
    wndcls.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
    wndcls.lpszMenuName = NULL;
    // Specify your own class name for using FindWindow later
    wndcls.lpszClassName = _T("MyNewClass");

    // Register the new class and exit if it fails
    if(!AfxRegisterClass(&wndcls))
    {
       AfxMessageBox(_T("Class Registration Failed\n"));
       return FALSE;
    }
   /********************************************************************/
   // Other code here...
   }

How much of that applies to what I need to do?
------------------
"David Webber" <dave@musical-dot-demon-dot-co.uk> wrote in message
news:uxnFklsuIHA.4376@TK2MSFTNGP06.phx.gbl...

"SteveR" <maxsrussellatremovethisembarqmail.com> wrote in message
news:%23tma%23QsuIHA.5268@TK2MSFTNGP06.phx.gbl...

My installer calls FindWindow on my app, using the title parameter, and
that works fine, but I would rather use the class. I have a pretty
standard SDI and have never before had a reason to work with the name
app's window class. How do I know what that is?


In an MDI app it works as follows IIRC.

The class name is an element of the CREATESTRUCT which is passed to
CMDIFrameWnd::PreCreateWindow().

I believe MFC defines its own and if you look for windows of that class
you'll pick up almost anything created with MFC.

So the thing to do is override CMDIFrameWnd::PreCreateWindow() with your
own CMainFrame::PreCreateWindow() and replace the class name with your own
before calling CMDIFrameWnd::PreCreateWindow(). Then you can look for
your own application with that class name.

However you must also register your class name - I do it using
AfxRegisterClass()

[I do this so that I can check if my app is already running, and abort a
second instance if it tries to get going, passing its command line
parameters to the already running instance. That way double clicking on
a document file in explorer will open it in an already-running instance if
there is one, rather than launching a second.]

Dave
--
David Webber
Author of 'Mozart the Music Processor'
http://www.mozart.co.uk
For discussion/support see
http://www.mozart.co.uk/mozartists/mailinglist.htm

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