BackgroundAudioTask.MyBackgroundAudioTask.BackgroundMediaPlayer_MessageReceivedFromForeground C# (CSharp) Method

        void BackgroundMediaPlayer_MessageReceivedFromForeground(object sender, MediaPlayerDataReceivedEventArgs e)
        {
            Uri currentTrackId;
            AppSuspendedMessage appSuspendedMessage;
            if (MessageService.TryParseMessage(e.Data, out appSuspendedMessage))
            {
                Debug.WriteLine("App suspending"); // App is suspended, you can save your task state at this point
                foregroundAppState = AppState.Suspended;
                currentTrackId = GetCurrentTrackId();
                ApplicationSettingsHelper.SaveSettingsValue(ApplicationSettingsConstants.TrackId, currentTrackId == null ? null : currentTrackId.ToString());
                return;
            }

            AppResumedMessage appResumedMessage;
            if (MessageService.TryParseMessage(e.Data, out appResumedMessage))
            {
                Debug.WriteLine("App resuming"); // App is resumed, now subscribe to message channel
                foregroundAppState = AppState.Active;
                return;
            }

            currentTrackId = GetCurrentTrackId();
            ApplicationSettingsHelper.SaveSettingsValue(ApplicationSettingsConstants.TrackId, currentTrackId == null ? null : currentTrackId.ToString());
            StartPlaybackMessage startPlaybackMessage;
            if (MessageService.TryParseMessage(e.Data, out startPlaybackMessage))
            {
                //Foreground App process has signalled that it is ready for playback
                Debug.WriteLine("Starting Playback");
                StartPlayback();
                return;
            }

            SkipNextMessage skipNextMessage;
            if (MessageService.TryParseMessage(e.Data, out skipNextMessage))
            {
                // User has chosen to skip track from app context.
                Debug.WriteLine("Skipping to next");
                SkipToNext();
                return;
            }

            SkipPreviousMessage skipPreviousMessage;
            if (MessageService.TryParseMessage(e.Data, out skipPreviousMessage))
            {
                // User has chosen to skip track from app context.
                Debug.WriteLine("Skipping to previous");
                SkipToPrevious();
                return;
            }

            TrackChangedMessage trackChangedMessage;
            if (MessageService.TryParseMessage(e.Data, out trackChangedMessage))
            {
                var index = playbackList.Items.ToList().FindIndex(i => new Uri(i.Source.CustomProperties[TrackIdKey].ToString()) == trackChangedMessage.TrackId);
                Debug.WriteLine("Skipping to track " + index);
                smtc.PlaybackStatus = MediaPlaybackStatus.Changing;
                playbackList.MoveTo((uint)index);

                // TODO: Work around playlist bug that doesn't continue playing after a switch; remove later
                BackgroundMediaPlayer.Current.Play();
                return;
            }

            UpdatePlaylistMessage updatePlaylistMessage;
            if (MessageService.TryParseMessage(e.Data, out updatePlaylistMessage))
            {
                CreatePlaybackList(updatePlaylistMessage.Songs);
                return;
            }
        }