/// <summary>
 /// Initializes a new instance of the <see cref="NavigationTransitionSelector"/> class.
 /// </summary>
 /// <param name="navigationService">The navigation service.</param>
 /// <param name="transitionRegistry">The transition registry.</param>
 public NavigationTransitionSelector(NavigationService navigationService, NavigationTransitionRegistry transitionRegistry)
 {
     BackStack                          = new Stack <NavigationTransition>();
     ForwardStack                       = new Stack <NavigationTransition>();
     this.transitionRegistry            = transitionRegistry;
     this.navigationService             = navigationService;
     this.navigationService.Navigating += HandleContentNavigating;
     this.navigationService.Navigated  += HandleContentNavigated;
 }
 /// <summary>
 /// Initializes a new instance of the <see cref="NavigationTransitionSelector"/> class.
 /// </summary>
 /// <param name="navigationService">The navigation service.</param>
 /// <param name="transitionRegistry">The transition registry.</param>
 public NavigationTransitionSelector(NavigationService navigationService, NavigationTransitionRegistry transitionRegistry)
 {
     BackStack = new Stack<NavigationTransition>();
     ForwardStack = new Stack<NavigationTransition>();
     this.transitionRegistry = transitionRegistry;
     this.navigationService = navigationService;
     this.navigationService.Navigating += HandleContentNavigating;
     this.navigationService.Navigated += HandleContentNavigated;
 }