These event arguments contain information about the navigation that was requested, and are passed to handlers of the Navigating event, which is implemented by the following:

• NavigationService..::.Navigating

• NavigationWindow..::.Navigating

• Frame..::.Navigating

• Application..::.Navigating

NavigatingCancelEventArgs encapsulates the following details of the navigation request:

• Navigation Initiation: NavigationMode, Navigator, IsNavigationInitiator.

• Navigation Content: Uri, Content.

• Navigation Request: WebRequest.

• Navigation State: ExtraData, ContentStateToSave, TargetContentState.

This information allows you to both evaluate the nature of the navigation request, and view and update specified request details before navigation occurs.

Based on the navigation request information provided by NavigatingCancelEventArgs, or based on application-specific state or code, you can completely prevent navigation by setting the Cancel property to true (by default, Cancel is false).

The following example shows how to handle Navigating to detect whether a request to refresh static content was made, and if one was, how to cancel the request.

Navigating.

Private Sub NavigationService_Navigating(ByVal sender As Object, ByVal e As NavigatingCancelEventArgs)
    ' Don't allow refreshing of a static page
    If (e.NavigationMode = NavigationMode.Refresh) AndAlso (e.Uri.OriginalString = "StaticPage.xaml") Then
        e.Cancel = True
    End If
End Sub

void NavigationService_Navigating(object sender, NavigatingCancelEventArgs e)
{
    // Don't allow refreshing of a static page
    if ((e.NavigationMode == NavigationMode.Refresh) &&
        (e.Uri.OriginalString == "StaticPage.xaml"))
    {
        e.Cancel = true;
    }
}

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference