NavigationService.Navigate Method (Uri)
Navigate asynchronously to content that is specified by a uniform resource identifier (URI).
Assembly: PresentationFramework (in PresentationFramework.dll)
The value of source can be a Web URL or a valid pack URI (see Pack URIs in WPF).
Navigate will navigate to the URI specified by source if the following conditions are true:
If source is null, the existing content (Content) is cleared.
When downloading Web content, you may receive a Web exception (for example, 404: File Not Found). You can handle such exceptions from NavigationFailed.
You can use Navigate to navigate to a content fragment. If the content identified by the URI is the current content, it is not downloaded again.