How to Use Timer in MFC Dialog based Application?

_AFXWIN_INLINE UINT_PTR CWnd::SetTimer(UINT_PTR nIDEvent, UINT nElapse,
    void (CALLBACK* lpfnTimer)(HWND, UINT, UINT_PTR, DWORD))

You may want to do something like

UINT_PTR myTimer = SetTimer (1, 1000, null); // one event every 1000 ms = 1 s

and react to the ON_TIMER event in your window's event handler:

void CMyView::OnTimer (UINT_PTR nIdEvent)
{
if (nIdEvent == 1)
    // handle timer event
}

Alternatively you can pass a pointer to a function handling the timer events. Keeping the handle to the timer allows you to turn it off using KillTimer() in case you have to.