Display Multiple Pages in Silverlight: Figure 1: Display Several Silverlight "Forms" Simultaneously.
Silverlight runs in a browser, so there's only one Page that serves as the RootVisual or visual entry point for your application. You can't change the RootVisual as your application runs. When your application needs to display several "forms" at different times, create one Page to serve as a navigation container and switch out user controls that contain the "forms" of your application. The Page might be empty or contain visual elements common to all of your user controls.