please dont rip this site Prev Next

WM_MDIACTIVATE Overview  Group

An application sends the WM_MDIACTIVATE message to a multiple document interface (MDI) client window to instruct the client window to activate a different MDI child window. As the client window processes this message, it sends WM_MDIACTIVATE to the child window being deactivated and to the child window being activated.


// Message sent to MDI client 

wParam = (WPARAM) (HWND) hwndChildAct; // child to activate 

lParam = 0;                            // not used; must be zero 


// Message received by MDI child 

hwndChildDeact = (HWND) wParam;        // child being deactivated 

hwndChildAct = (HWND) lParam;          // child being activated 



In messages sent to an MDI client window:

Value of wParam. Identifies the MDI child window to be activated.

In messages received by an MDI child window:

Value of wParam. Identifies the MDI child window being deactivated.
Value of lParam. Identifies the MDI child window being activated.

Return Values

If an application sends this message to an MDI client window, the return value is zero. An MDI child window should return zero if it processes this message.


An MDI child window is activated independently of the MDI frame window. When the frame window becomes active, the child window last activated by using the WM_MDIACTIVATE message receives the WM_NCACTIVATE message to draw an active window frame and title bar; the child window does not receive another WM_MDIACTIVATE message.

See Also


file: /Techref/os/win/api/win32/mess/src/msg25_11.htm, 2KB, , updated: 2000/4/7 11:20, local time: 2023/12/5 13:35,

 ©2023 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
Please DO link to this page! Digg it! / MAKE!


After you find an appropriate page, you are invited to your to this massmind site! (posts will be visible only to you before review) Just type a nice message (short messages are blocked as spam) in the box and press the Post button. (HTML welcomed, but not the <A tag: Instead, use the link box to link to another page. A tutorial is available Members can login to post directly, become page editors, and be credited for their posts.

Link? Put it here: 
if you want a response, please enter your email address: 
Attn spammers: All posts are reviewed before being made visible to anyone other than the poster.
Did you find what you needed?


Welcome to!


Welcome to!