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 win32 msgs: WM_MDIACTIVATE

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.

To send this message, call the SendMessage function with the following parameters.

    SendMessage( 
      (HWND) hWnd,              // handle to destination window 
      WM_MDIACTIVE,             // message to send
      (WPARAM) wParam,          // handle to child window (HWND)
      (LPARAM) lParam           // not used; must be zero
    );

Parameters

• wParam Handle to the MDI child window to be activated.
• lParam This parameter is not used.

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.

Remarks

As the client window processes this message, it sends WM_MDIACTIVATE to the child window being deactivated and to the child window being activated. The message parameters received by an MDI child window are as follows:

• wParam Handle to the MDI child window being deactivated.
• lParam Handle to the MDI child window being activated. 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.

Requirements

  Windows NT/2000 or later: Requires Windows NT 3.1 or later.
  Windows 95/98/Me: Requires Windows 95 or later.
  Header: Declared in Winuser.h; include Windows.h.

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Notebook exported on Monday, 7 July 2008, 18:56:50 PM Eastern Daylight Time