MFC, Subclassing a window

Subclassing a window

Author	Message
Mark #1 / 6	Subclassing a window Hi all, A newbie question I'm sure but how do you subclass a window using CWnd::SubclassWindow ? I get an assert in a method called by SubclassWindow: BOOL CWnd::SubclassWindow(HWND hWnd) { if (!Attach(hWnd)) return FALSE; BOOL CWnd::Attach(HWND hWndNew) { ASSERT(m_hWnd == NULL); // only attach once, detach on destroy << ASSERT HERE!!!! ASSERT(FromHandlePermanent(hWndNew) == NULL); // must not already be in permanent map It seems it's already been subclassed? Thanx for any insight Sham
Sat, 16 Apr 2005 03:02:41 GMT

Jeff Partc #2 / 6	Subclassing a window Quote: > Hi Jeff, > Well I want to intercept some messages going to my CWnd derived class and > handle them directly, perhaps passing them on. Is there another way to do > this? Well my first response is to state that that's what the MESSAGE_MAP is for, and the MESSAGE_MAP is why MFC has already subclassed the HWND to the CWnd. What part of this scheme doesn't work for you? -- Jeff Partch [MVP]
Sat, 16 Apr 2005 03:23:22 GMT

Mark #3 / 6	Subclassing a window Hi Jeff, Well I want to intercept some messages going to my CWnd derived class and handle them directly, perhaps passing them on. Is there another way to do this? Thanx for any ideas Mark Quote: > > Hi all, > > A newbie question I'm sure but how do you subclass a window using > > CWnd::SubclassWindow ? > > I get an assert in a method called by SubclassWindow: > > BOOL CWnd::SubclassWindow(HWND hWnd) > > { > > if (!Attach(hWnd)) > > return FALSE; > > BOOL CWnd::Attach(HWND hWndNew) > > { > > ASSERT(m_hWnd == NULL); // only attach once, detach on destroy << > > ASSERT HERE!!!! > > ASSERT(FromHandlePermanent(hWndNew) == NULL); > > // must not already be in permanent map > > It seems it's already been subclassed? > Yes, its already been subclassed as far as MFC is concerned. What are you trying to accomplish? - Hide quoted text - - Show quoted text - Quote: > -- > Jeff Partch [MVP]
Sat, 16 Apr 2005 03:15:31 GMT

Mark #4 / 6	Subclassing a window I want to intercept messages meant for one class (A) with another (B). Obviously I have my reasons for this. For example, I want to get the right click sent to class A sent first to my proxy class B. Then I will send it on to class A as needed. Mark Quote: > > Hi Jeff, > > Well I want to intercept some messages going to my CWnd derived class and > > handle them directly, perhaps passing them on. Is there another way to do > > this? > Well my first response is to state that that's what the MESSAGE_MAP is for, and the MESSAGE_MAP is Quote: > why MFC has already subclassed the HWND to the CWnd. What part of this scheme doesn't work for you? Quote: > -- > Jeff Partch [MVP]
Sat, 16 Apr 2005 03:34:13 GMT

Jeff Partc #5 / 6	Subclassing a window Quote: > I want to intercept messages meant for one class (A) with another (B). > Obviously I have my reasons for this. For example, I want to get the right > click sent to class A sent first to my proxy class B. Then I will send it on > to class A as needed. See if something like Paul DiLascia's CSubclassWnd is what you have in mind... http://www.microsoft.com/msj/defaultframe.asp?page=/msj/0697/c++0697.htm -- Jeff Partch [MVP]
Sat, 16 Apr 2005 04:13:35 GMT

Mark #6 / 6	Subclassing a window I will check it out. Thanx Jeff! Quote: > > I want to intercept messages meant for one class (A) with another (B). > > Obviously I have my reasons for this. For example, I want to get the right > > click sent to class A sent first to my proxy class B. Then I will send it on > > to class A as needed. > See if something like Paul DiLascia's CSubclassWnd is what you have in mind... > http://www.microsoft.com/msj/defaultframe.asp?page=/msj/0697/c++0697.htm > -- > Jeff Partch [MVP]
Sat, 16 Apr 2005 05:34:49 GMT

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