Is there Windows system event on active window changed?

Question

The desktop application I\'m developing need to know what windows were active while the application was run. Currently it performs GetForegroundWindow() call (o

Answer 1

Yes, you can use SetWinEventHook function.

hEvent = SetWinEventHook(EVENT_SYSTEM_FOREGROUND , 
    EVENT_SYSTEM_FOREGROUND , NULL, 
    WinEventProcCallback, 0, 0, 
    WINEVENT_OUTOFCONTEXT | WINEVENT_SKIPOWNPROCESS);

.......

VOID CALLBACK WinEventProcCallback ( HWINEVENTHOOK hWinEventHook, DWORD dwEvent, HWND hwnd, LONG idObject, LONG idChild, DWORD dwEventThread, DWORD dwmsEventTime)
{
    /* your code here */
}

Answer 2

There's the WM_ACTIVATE message, which is sent to the activated and deactivated windows.