截获某个窗口的WM_TIMER消息

我想要截获某个窗口的WM_TIMER消息,但是怎么都栏不到?
哪位兄弟知道哪边写错了?

SetWindowsHookEx(WH_CALLWNDPROC,(HOOKPROC)WndRProc,hinsT,0);LRESULT CALLBACK WndRProc(int nCode, WPARAM wParam, LPARAM lParam)
{
if (nCode == HC_ACTION)
{
CWPSTRUCT *PPmsg=(CWPSTRUCT *)lParam; switch (PPmsg->message)
{
//pcwp->message = WM_NULL;
case WM_TIMER:
{
MessageBox(0,"1111","1111",MB_OK);
break;
}
........................
........
}