Navigation Frame in Silverlight

The Navigation Frame is a "Master Page" for Silverlight Applications.

You can do 3 basic things on your button click event:
1. Go back to the previous page:

this.navigationframe.GoBack();

2. Go to specific page:

this.ContentFrame.Navigate(new System.Uri("yourpage.xaml", System.UriKind.RelativeOrAbsolute));

3. Go forward if you are in previous page:

this.ContentFrame.GoForward();

So, you cannot close a page, you can navigate through them.

Hope it helps and answers your question.