Gets the navigation service that the host of the page is using to manage navigation.
Assembly: PresentationFramework (in PresentationFramework.dll)
Pages often need to integrate with their host's navigation to provide in-page navigation support. However, because a page may not know what its host will be at run time, it cannot integrate directly with its host's navigation members to do so.
Instead, it can attempt to use a navigation service, which is a service that supports browser-style navigation and is encapsulated by the NavigationService class. You cannot create your own NavigationService instance, though. Instead, host types such as NavigationWindow, Frame, or a browser create their own NavigationService instance that you can access from the property.
The navigation service that is returned from the property is the instance of the NavigationService class that is managed by the first navigator up the visual tree. If one is not found, Nothing is returned, indicating a page's host does not support navigation.
The Window class does not support navigation and does not provide a navigation service.
The following example shows how a page can check if a navigation service is available and, if so, use it to navigate back to the previous page.
Partial Public Class HomePage Inherits Page Public Sub New() InitializeComponent() ' Don't allow back navigation if no navigation service If Me.NavigationService IsNot Nothing Then Me.goBackButton.IsEnabled = False End If End Sub Private Sub goBackButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs) ' Go to previous entry in journal back stack If Me.NavigationService.CanGoBack Then Me.NavigationService.GoBack() End If End Sub End Class