Thread.Sleep doesn\'t seem to be supported in .NET for Windows Store apps.
For example, this
System.Threading.Thread.Sleep(1000);
Windows Store apps embrace asynchrony - and an "asynchronous pause" is provided by Task.Delay. So within an asynchronous method, you'd write:
await Task.Delay(TimeSpan.FromSeconds(30));
... or whatever delay you want. The asynchronous method will continue 30 seconds later, but the thread will not be blocked, just as for all await expressions.