How to reset a timer in C#?

All the timers have the equivalent of Start() and Stop() methods, except System.Threading.Timer.

So an extension method such as...

public static void Reset(this Timer timer)
{
  timer.Stop();
  timer.Start();
}

...is one way to go about it.

For System.Timers.Timer, according to MSDN documentation, http://msdn.microsoft.com/en-us/library/system.timers.timer.enabled.aspx:

If the interval is set after the Timer has started, the count is reset. For example, if you set the interval to 5 seconds and then set the Enabled property to true, the count starts at the time Enabled is set. If you reset the interval to 10 seconds when count is 3 seconds, the Elapsed event is raised for the first time 13 seconds after Enabled was set to true.

So,

    const double TIMEOUT = 5000; // milliseconds

    aTimer = new System.Timers.Timer(TIMEOUT);
    aTimer.Start();     // timer start running

    :
    :

    aTimer.Interval = TIMEOUT;  // restart the timer

I always do ...

myTimer.Stop();
myTimer.Start();

... is that a hack? :)

Per comment, on Threading.Timer, it's the Change method ...

dueTime Type: System.Int32 The amount of time to delay before the invoking the callback method specified when the Timer was constructed, in milliseconds. Specify Timeout.Infinite to prevent the timer from restarting. Specify zero (0) to restart the timer immediately.