How to automatically play the next file in playlist when a file have finished?

Question

I have done my own music player in C# WPF. But, I can't make it automatically play the next file in the playlist when a song have finished. I have a slider to show the play progress, a checkbox and next-previous buttons.

Here is the code for the Next button:

private void btnNext_Click(object sender, RoutedEventArgs e)
{
    if (listBox.SelectedIndex < listBox.Items.Count - 1)
    {
       listBox.SelectedIndex = listBox.SelectedIndex + 1;
       TagLib.File tagFile = TagLib.File.Create((listBox.SelectedValue).ToString());
       string album = tagFile.Tag.Album;
       string artist = tagFile.Tag.FirstAlbumArtist;
       string title = tagFile.Tag.Title;
       uint year = tagFile.Tag.Year;
       string genre = tagFile.Tag.FirstGenre;
       lblName.Content = artist + " - " + title;
       lblAlbum.Content = album;
       lblArtist.Content = artist;
       lblTitle.Content = title;
       lblYear.Content = year;
       lblGenre.Content = genre;
       lblBit.Content = tagFile.Properties.AudioBitrate + " kbps";
       lblTime2.Content = tagFile.Properties.Duration.ToString(@"mm\:ss");
       mediaPlayer.Open(new Uri((listBox.SelectedValue).ToString()));
       mediaPlayer.Play();
       btnPlay2.Visibility = Visibility.Hidden;
       btnPause.IsEnabled = true;
    } 
}

And here are the codes for the slider:

private void sliProgress_DragStarted(object sender, DragStartedEventArgs e)
{
    userIsDraggingSlider = true;
}

private void sliProgress_DragCompleted(object sender, DragCompletedEventArgs e)
{
    userIsDraggingSlider = false;
    mediaPlayer.Position = TimeSpan.FromSeconds(sliProgress.Value);
}

private void sliProgress_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
{
    lblTime.Content = TimeSpan.FromSeconds(sliProgress.Value).ToString(@"mm\:ss");
}

I have tried to implement the procedure in the Next button into that checkbox when clicked by comparing when maximum duration of a song/file (lblTime2) and progressing duration (lblTime) is equal:

private void radioAll_Checked(object sender, RoutedEventArgs e)
    {
        if (lblTime.Content.ToString() == lblTime2.Content.ToString())
        {
            if (listBox.SelectedIndex < listBox.Items.Count - 1)
            {
                listBox.SelectedIndex = listBox.SelectedIndex + 1;
                TagLib.File tagFile = TagLib.File.Create((listBox.SelectedValue).ToString());
                string album = tagFile.Tag.Album;
                string artist = tagFile.Tag.FirstAlbumArtist;
                string title = tagFile.Tag.Title;
                uint year = tagFile.Tag.Year;
                string genre = tagFile.Tag.FirstGenre;
                lblName.Content = artist + " - " + title;
                lblAlbum.Content = album;
                lblArtist.Content = artist;
                lblTitle.Content = title;
                lblYear.Content = year;
                lblGenre.Content = genre;
                lblBit.Content = tagFile.Properties.AudioBitrate + " kbps";
                lblTime2.Content = tagFile.Properties.Duration.ToString(@"mm\:ss");
                mediaPlayer.Open(new Uri((listBox.SelectedValue).ToString()));
                mediaPlayer.Play();
            }
        }
    }

Unfortunately, it can't worked at all. Am I missed something? What should I do?

Answer 1

Subscribe to the MediaPlayer.MediaEnded event and handle appropriately.

MSDN:

Occurs when the media has finished playback

e.g.

mediaPlayer.MediaEnded += OnMediaEnded;

mediaPlayer.Open(new Uri((listBox.SelectedValue).ToString()));
mediaPlayer.Play();
.
.
.

private void OnMediaEnded(object sender, EventArgs e) 
{
    // play next song
}