private static void ContentLoaderPropertyChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            AuthorizationNavigationManager manager = (AuthorizationNavigationManager)sender;

            if (!(e.NewValue is AuthorizationContentLoader))
            {
                manager._frame.ContentLoader = new AuthorizationContentLoader(
                    manager._frame,
                    (INavigationContentLoader)e.NewValue ?? new PageResourceContentLoader());
            }

            manager.SetDefaultSource(manager._frame.Source);
        }
        private static void SourcePropertyChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            AuthorizationNavigationManager manager = (AuthorizationNavigationManager)sender;

            manager.SetDefaultSource((Uri)e.NewValue);
        }