public void AddStoryArtist(ObservableChangedCollection <StoryArtistEditModel> storyArtists, int?storyId) { if (storyId.HasValue) { if (!StoryArtist.Any(s => s.StoryId == storyId.Value)) { if (!storyArtists.Any(s => s.StoryId == storyId.Value)) { StoryArtist.Add(new StoryArtistEditModel { ArtistId = Id, StoryId = storyId }); } StoryArtist = storyArtists; } } }