NavigationService.GetNavigationService(DependencyObject) Method

Definition

Namespace:

System.Windows.Navigation

Assembly:

PresentationFramework.dll

Gets a reference to the NavigationService for the navigator whose content contains the specified DependencyObject.

public:
 static System::Windows::Navigation::NavigationService ^ GetNavigationService(System::Windows::DependencyObject ^ dependencyObject);

public static System.Windows.Navigation.NavigationService GetNavigationService (System.Windows.DependencyObject dependencyObject);

static member GetNavigationService : System.Windows.DependencyObject -> System.Windows.Navigation.NavigationService

Public Shared Function GetNavigationService (dependencyObject As DependencyObject) As NavigationService

Parameters

dependencyObject

DependencyObject

The DependencyObject in content that is hosted by a navigator.

Returns

NavigationService

A reference to the NavigationService for the navigator whose content contains the specified DependencyObject; can be null in some cases.

Exceptions

ArgumentNullException

The dependencyObject parameter is null.

Examples

The following example shows how a UserControl can retrieve a navigation service by calling GetNavigationService.

void getNavigationServiceButton_Click(object sender, RoutedEventArgs e) {
    // Retrieve first navigation service up the content tree
    NavigationService svc = NavigationService.GetNavigationService(this.getNavigationServiceButton);
    if (svc != null)
    {
        // Use navigation service

Private Sub getNavigationServiceButton_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    ' Retrieve first navigation service up the content tree
    Dim svc As NavigationService = NavigationService.GetNavigationService(Me.getNavigationServiceButton)
    If svc IsNot Nothing Then
        ' Use navigation service

    }
}

    End If
End Sub

Remarks

A navigator has a NavigationService that handles content navigation. WPF has two navigators: NavigationWindow and Frame. To process navigation requests and manage navigation lifetime, a navigator uses the WPF navigation service, which is implemented as the NavigationService class. Content that is hosted by a navigator can get a reference to the navigator's NavigationService by calling the GetNavigationService method.

GetNavigationService returns null when the dependencyObject:

• Is a NavigationWindow.

• Is a Frame that:

  1. Is hosted by another navigator.

  2. Has its JournalOwnership property set to UsesParentJournal.

• Is not part of content that is hosted by a navigator.

WPF offers two shortcuts for acquiring a reference to the NavigationService:

• The NavigationService that processed the navigation to a Page can be accessed from the Page itself by getting the value of its Page.NavigationService property.

• The NavigationService that is used by a Frame to process navigation can be accessed by getting the value of the NavigationService property.