The Thread Class
The most straightforward way to create a multithreaded Silverlight application is to use the Thread class from the System.Threading namespace. Each Thread object represents a separate thread of execution.
To use the Thread class, you begin by creating a new Thread object, at which point you supply a delegate to the method you want to invoke asynchronously. A Thread object can point to only a single method. This signature of this method is limited in several ways. It can't have a return value, and it must have either no parameters (in which case it matches the ThreadStart delegate) or a single object parameter (in which case it matches the ParameterizedThreadStart delegate).
For example, if you have a method like this: