public IList <AddToPlaylistDto> GetAddToPlaylists(int userId, int trackId) { if (userId <= 0) { throw new ArgumentOutOfRangeException(nameof(userId)); } if (trackId <= 0) { throw new ArgumentOutOfRangeException(nameof(trackId)); } var track = _playlistRepository.GetById <Track>(trackId) ?? throw new ArgumentNullException(nameof(trackId)); var user = _playlistRepository.GetById <User>(userId) ?? throw new ArgumentNullException(nameof(userId)); var addToPlaylistDtos = _playlistRepository.GetAddToPlaylists(user.Id); foreach (var dto in addToPlaylistDtos) { dto.Artwork = _playlistRepository.GetArtwork(dto.PlaylistId).Value; dto.HasTrack = _playlistRepository.IsTrackInPlaylist(track.Id, dto.PlaylistId); dto.CreatorUserName = user.UserName; } return(addToPlaylistDtos); }