Re: Overriding WindowProc

From:

"Alexander Nickolov" <agnickolov@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 13 Apr 2007 15:29:56 -0700

Message-ID:

<#QDpEthfHHA.5044@TK2MSFTNGP05.phx.gbl>

Don't forget to reserve the space in the window class. Otherwise
you are writing in unallocated memory (or worse - overwriting
somebody else's memory). Come to think of it, if you controlled
the window class you wouldn't need to replace the window proc
in the first place. Shortly - your "solution" is unacceptable.

--
=====================================
Alexander Nickolov
Microsoft MVP [VC], MCSD
email: agnickolov@mvps.org
MVP VC FAQ: http://vcfaq.mvps.org
=====================================

"NickP" <a@a.com> wrote in message
news:OZtfquafHHA.4772@TK2MSFTNGP05.phx.gbl...

Hi again Chris,

That worked great. I found a nice way of storing the old WNDPROC by
using SetWindowLong and GWL_USERDATA on the window, then it can be
obtained via the static callback without any need for an external variable
reference.

Nick.

"NickP" <a@a.com> wrote in message
news:erqkd0ZfHHA.1456@TK2MSFTNGP04.phx.gbl...

Hi Chris,

Thanks for your help, I shall give that a try!

Nick.

"Chris Taylor" <chris_taylor_za@hotmail.com> wrote in message
news:D63D6F88-8DDF-4D37-960A-414CF229A133@microsoft.com...

Hi,

If SetWindowLongPtr is successfull it returns the previous value in your
case that would be the pointer to the previous windows procedure. You
should store this and in your window procedure you should use
CallWindowProc to pass the messages to the original window procedure.

Hope this helps

--
Chris Taylor
http://dotnetjunkies.com/weblog/chris.taylor

"NickP" <a@a.com> wrote in message
news:ujjCXPSfHHA.4596@TK2MSFTNGP05.phx.gbl...

Hi there,

   I am using the following code to overwrite a window proc,

   -------------

   ::SetWindowLongPtr(pWndFocusWindow, GWLP_WNDPROC, (LONG)OnHookMsg);

   ...

   LRESULT WINAPI CMainFrame::OnHookMsg(HWND hWnd, UINT uMsg, WPARAM
wParam, LPARAM lParam)
   {
       return(::DefWindowProc(hWnd, uMsg, wParam, lParam));
   }

   -------------

   OnHookMsg is a static method of CMainFrame and pWndFocusWindow is a
child window of CMainFrame that has just obtained window focus.

   OnHookMsg fires but then the window locks up, I presume tis is
because a value has not been returned to the original SendMessage call.
But I have included DefWindowProc, so surely this should work right?

   Basically I don't want to effect any of the messages, simple monitor
them.

   Many thanks in advance.

Nick.