The TimerEventHandler Callback Function. An application-defined callback function that processes WM_TIMER messages. The TIMERPROC type defines a pointer to this callback function. TimerProc is a placeholder for the application-defined function name

private delegate void TimerEventHandler(UInt32 id, UInt32 msg, ref UInt32 userCtx, UInt32 rsv1, UInt32 rsv2);

Private Delegate Sub TimerEventHandler(ByVal id As UInt32, ByVal msg As UInt32, ByRef userCtx As UInt32, ByVal rsv1 As UInt32, ByVal rsv2 As UInt32)

Documentation

[TimerEventHandler] on MSDN

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