如何在WP7 BGM中循环播放音乐？

private void button1_Click(object sender, RoutedEventArgs e)
{
    MediaElement Lala = 
        ((MediaElement)App.Current.Resources[\"backgroundMusic\"]).Stop();

    if (Lala == true)
    {
        ((MediaElement)App.Current.Resources[\"backgroundMusic\"]).Play();
    }

<Application.Resources>
    <MediaElement x:Name=\"backgroundMusic\" Source=\"Nyan.mp3\" AutoPlay=\"True\" Volume=\"1\" />
</Application.Resources>

MediaElement

if (Lala == true)

MediaEnded=\"\"

 <MediaElement x:Name=\"backgroundMusic\" Source=\"Nyan.mp3\" AutoPlay=\"True\" Volume=\"1\" MediaEnded=\"DoThisWhenMediaEnds\" />

 private void DoThisWhenMediaEnds(object sender, RoutedEventArgs e)
 {
    //what to do when the media has ended. In this case:
    backgroundMusic.Play();
 }