如何在文件播放完畢後自動播放播放列表中的下一個文件？

Question

我已經在C＃WPF中完成了我自己的音樂播放器。但是，當歌曲結束時，我無法自動播放播放列表中的下一個文件。我有一個滑塊來顯示播放進度，複選框和下一個上一個按鈕。

這裏是下一步按鈕的代碼：

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; 
    } 
} 

這裏是滑塊代碼：

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"); 
} 

我試圖實現下一步按鈕的程序到該複選框當通過比較當歌曲/文件的最大持續時間（lblTime2）和進度持續時間（lblTime）相等時點擊時：

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，它根本無法工作。我錯過了什麼嗎？我該怎麼辦？

Answer 1

訂閱MediaPlayer.MediaEnded事件並正確處理。

MSDN：

時發生的媒體已完成播放

例如

mediaPlayer.MediaEnded += OnMediaEnded; 

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

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