public FavoritesViewModel([NotNull] INavigationService navigationService, [NotNull] FavoritedItemsManager favoritedItemsManager, [NotNull] FlurryPublisher flurryPublisher) { if (navigationService == null) { throw new ArgumentNullException("navigationService"); } if (favoritedItemsManager == null) { throw new ArgumentNullException("favoritedItemsManager"); } if (flurryPublisher == null) { throw new ArgumentNullException("flurryPublisher"); } _navigationService = navigationService; flurryPublisher.PublishPageLoadedFavorites(); Items = new ObservableCollection <FavoritedItemViewModel>( favoritedItemsManager.GetFavorites().ToViewModels(_navigationService)); AddCommand = new SimpleCommand(AddNewFavorite); }