public CallbackContext(WaitableTimerCallback cb, object state)
{
callback = cb;
callbackState = state;
}
public int Change(TimeSpan dueTime, int period, WaitableTimerCallback callback, object state, bool resume)
{
long dueTicks = dueTime.Ticks;
if (dueTicks < 0)
{
throw new ArgumentException("dueTime cannot be negative");
}
return ChangeInternal(-dueTicks, period, callback, state, resume);
}
private int ChangeInternal(long dueTime, int period, WaitableTimerCallback callback, object state, bool resume)
{
if (period < 0)
{
throw new ArgumentException("period cannot be negative.");
}
// CallbackContext is used to avoid a race condition.
CallbackContext context = null;
Win32WaitableTimer.TimerAPCProc completionCallback = null;
if (callback != null)
{
context = new CallbackContext(callback, state);
completionCallback = context.TimerTick;
}
// Have to do this because SetWaitableTimer needs a reference
long due = dueTime;
bool rslt = Win32WaitableTimer.SetWaitableTimer(
SafeWaitHandle,
ref due,
period,
completionCallback,
IntPtr.Zero,
resume);
if (!rslt)
{
throw GetWin32Exception();
}
TimerCompletionCallback = context;
return Marshal.GetLastWin32Error();
}
public int Change(DateTime dueTime, int period, WaitableTimerCallback callback, object state, bool resume)
{
long dueTicks = dueTime.ToUniversalTime().Ticks;
return ChangeInternal(dueTicks, period, callback, state, resume);
}
