I've been playing with some timers and Web Services and I got stuck in a case where the background thread was trying to update the UI. Well, that's never going to happen. To update the UI you should use the UI thread. Let's see how we can call the UI thread from the background thread.
Consider this situation:
You have data that needs to be updated every minute. The data is loaded by calling a web service.
For the update you can use the Timer class. Both the timer and the web service calls are executed asynchronously.