Question

When the user does something (touch on a StackPanel, in this case), I need to begin a timer of some sort (probably DispatcherTimer as I’m working in WPF) and if another touch happens again within a certain amount of time then I’ll call a method. As you can probably guess – this is to implement a double-tap functionality.

I’m assuming the best way to achieve this is through using threads (i.e. a child thread to increment a timespan which can be checked by the Main thread any time the StackPanel is touched again?)

Thanks,

Dan

Answer 1

You do not need to start another thread to do this.

Just take a timestamp of when the first tap happened and use this. You can then calculate the timespan by subtracting this time from the current time:

private DateTime _lastTap;
public void TapHandler()
{
  DateTime now = DateTime.UtcNow;
  TimeSpan span = now - lastTap;
  _lastTap = now;
  if (span < TimeSpan.FromSeconds(1)) {...}
}

Alternatively, as suggested by @DannyVarod, you can use a Stopwatch to achieve the same result (but with more accurate timing):

private Stopwatch _stopwatch = new Stopwatch();
public void TapHandler()
{
  TimeSpan elapsed = _stopwatch.Elapsed;
  _stopwatch.Restart();
  if (elapsed < TimeSpan.FromSeconds(1)) {...}
}