CWnd::SetTimer
Installs a system timer.
UINT_PTR SetTimer( UINT_PTR nIDEvent, UINT nElapse, void (CALLBACK* lpfnTimer )(HWND, UINT, UINT_PTR, DWORD ) );
The timer identifier of the new timer if the function is successful. An application passes this value to the KillTimer member function to kill the timer. Nonzero if successful; otherwise 0.
A time-out value is specified, and every time a time-out occurs, the system posts a WM_TIMER message to the installing application's message queue or passes the message to an application-defined TimerProc callback function.
The lpfnTimer callback function need not be named TimerProc, but it must be defined as follows:
void CALLBACK EXPORT TimerProc(
HWND hWnd, // handle of CWnd that called SetTimer
UINT nMsg, // WM_TIMER
UINT nIDEvent // timer identification
DWORD dwTime // system time
);
This example uses CWnd::SetTimer, CWnd::OnTimer, and CWnd::KillTimer to handle WM_TIMER messages. A timer is set up to send a WM_TIMER message to the main frame window every 2 seconds in OnStartTimer. OnStopTimer will stop the timer by calling CWnd::KillTimer. OnTimer was set up to handle WM_TIMER messages for the main frame window. In this example, the PC speaker will beep every 2 seconds.
void CMainFrame::OnStartTimer() { m_nTimer = SetTimer(1, 2000, 0); } void CMainFrame::OnStopTimer() { KillTimer(m_nTimer); } void CMainFrame::OnTimer(UINT nIDEvent) { MessageBeep(0xFFFFFFFF); // Beep // Call base class handler. CMDIFrameWnd::OnTimer(nIDEvent); }
