WM_ACTIVATE (Compact 2013)
This message is sent when a window is being activated or deactivated. This message is sent first to the window procedure of the top-level window being deactivated; it is then sent to the window procedure of the top-level window being activated.
WM_ACTIVATE fActive = LOWORD(wParam); fMinimized = (BOOL)HIWORD(wParam); hwndPrevious = (HWND) lParam;
Value of the low-order word of wParam. Specifies whether the window is being activated or deactivated. It is one of the following values.
Activated by some method other than a mouse click (for example, by a call to the SetActiveWindow function or by use of the keyboard interface to select the window).
Activated by a mouse click
Value of the high-order word of wParam. Specifies the minimized state of the window being activated or deactivated. A nonzero value indicates the window is minimized.
Handle to the window being activated or deactivated, depending on the value of the fActive parameter. If the value of fActive is WA_INACTIVE, hwndPrevious is the handle to the window being activated. If the value of fActive is WA_ACTIVE or WA_CLICKACTIVE, hwndPrevious is the handle to the window being deactivated. This handle can be NULL, and is always NULL when the window being activated and the window being deactivated are in separate processes.
An application should return zero if it processes this message.
- Default Action
If the window is being activated and is not minimized, the DefWindowProc function sets the keyboard focus to the window.
The fMinimized parameter must be zero.
If the window is activated by a mouse click, it also receives a WM_MOUSEACTIVATE message.