I have application, I send mouse_event
in timer event each 5 seconds,

mouse_event ( MOUSEEVENTF_LEFTDOWN, 10, 10, 0, 0 );
mouse_event ( MOUSEEVENTF_LEFTUP, 10, 10, 0, 0 );

the mouse event will send LBUTTONDOWN message, the thing is ok.
But If i switch to another application(my application now in background ),
the mouse_event cannot triigger, who can tell me how mouse event will
trigger when I switch to another application.

Jimmy

If I understand your question correctly, you want to stop generating the
mouse events when your application is no longer the active application, if
that is the case you can handle WM_ACTIVATEAPP and stop the timer when your
app is no longer active.

Hope this helps

Chris