如何在文件完成后自动播放播放列表中的下一个文件？

Question

我在C# WPF做过自己的音乐播放器。但是，我不能让它自动播放播放列表中的下一个文件时，一首歌已经完成。我有一个滑块来显示播放进度，一个复选框和下一个按钮。

下面是Next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;
    } 
}

下面是滑块的代码：

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");
}

我尝试在单击Next按钮时实现Next按钮中的过程，方法是比较歌曲/文件(lblTime2)的最大持续时间(lblTime)和进度持续时间(LblTime)是否相等：

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，它根本不能工作。我漏掉了什么吗？我该怎么办？

Answer 1

订阅MediaPlayer.MediaEnded事件并适当处理。

MSDN：

在媒体完成播放时发生。

例如：

mediaPlayer.MediaEnded += OnMediaEnded;

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

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