Why the DispatcherTimer doesn't work?

Hi,

I am alway using the DispatcherTimer with WPF or Silverlight. It is work great. I have been trying with Windows Azure Clould Serices. It doesn't work.

My cloud service

DispatcherTimer timer = new DispatcherTimer();
            timer.Interval = TimeSpan.FromMilliseconds(2);
            timer.Tick += (o, op) =>
                {
                    timer.Stop();
                    this.OnStart();
                };
            timer.Start();