如何在文件播放完毕后自动播放播放列表中的下一个文件？

Question

我已经在C＃WPF中完成了我自己的音乐播放器。但是，当歌曲结束时，我无法自动播放播放列表中的下一个文件。我有一个滑块来显示播放进度，复选框和下一个上一个按钮。

这里是下一步按钮的代码：

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; 
    } 
} 

这里是滑块代码：

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"); 
} 

我试图实现下一步按钮的程序到该复选框当通过比较当歌曲/文件的最大持续时间（lblTime2）和进度持续时间（lblTime）相等时点击时：

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(); 
      } 
     } 
    } 

不幸的是，它根本无法工作。我错过了什么吗？我该怎么办？

Answer 1

订阅MediaPlayer.MediaEnded事件并正确处理。

MSDN：

时发生的媒体已完成播放

例如

mediaPlayer.MediaEnded += OnMediaEnded; 

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

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