public MainViewModel(IFeedPreviewsLoader feedPreviews) { _feedPreviews = feedPreviews; AddSubscriptionCommand = NavigateCommand.WithParameter(() => Locator.Current.GetService<AddSubscriptionViewModel>()); Feeds = feedPreviews.CreateCollection().CreateDerivedCollection(f => f, null, FreshFirstOrderer); this.WhenActivated(d => feedPreviews.Load()); }