windows - Playing two sounds simultaneously c#

Question

I am creating a WP7 application that requires various sound effects to be played (on button press) over looped background music. The background music is initiated by pressing Button 1 and loops fine. When I press button3 (triggers a sound effect), the sound effect overlays on the background music fine on first press. However, when I press button3 again, the background music stops. I cannot figure out why this might be happening!? I have pasted the relevant portions of code below. Would appreciate any help.

public partial class MainPage : PhoneApplicationPage
{
    SoundEffect soundEffect;
    Stream soundfile;

    // Constructor
    public MainPage()
    {
        InitializeComponent();
    }



    static protected void LoopClip(SoundEffect soundEffect)
    {
        {
        SoundEffectInstance instance = soundEffect.CreateInstance();
        instance.IsLooped = true;
        FrameworkDispatcher.Update();
        instance.Play();
        }
    }

    public void PlaySound(string soundFile)
    {
        using (var stream = TitleContainer.OpenStream(soundFile))
        {

            var effect = SoundEffect.FromStream(stream);
            effect.Play();
        }
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        soundfile = TitleContainer.OpenStream("BackgroundMusic.wav");
        soundEffect = SoundEffect.FromStream(soundfile);  
        LoopClip(soundEffect);
    }


    private void button3_Click(object sender, RoutedEventArgs e)
    {
        PlaySound("sound3.wav");
    }

}

}

Answer 1

This should work if you are always working with Instances so change your code to this and it should clear up the problem:

public partial class MainPage : PhoneApplicationPage
{   

    SoundEffectInstance loopedSound = null;

    // Constructor
    public MainPage()
    {
        InitializeComponent();
    }

    static protected void LoopClip(SoundEffect soundEffect)
    {
        loopedSound = soundEffect.CreateInstance();
        loopedSound.IsLooped = true;
        loopedSound.Play();
    }

    public void PlaySound(string soundFile)
    {
        SoundEffect sound = SoundEffect.FromStream(Application.GetResourceStream(new Uri(soundFile, UriKind.Relative)).Stream);
        SoundEffectInstance instance = sound.CreateInstance();
        instance.Play();
    }

    private void button1_Click(object sender, RoutedEventArgs e)
    {
        SoundEffect sound = SoundEffect.FromStream(Application.GetResourceStream(new Uri(@"BackgroundMusic.wav", UriKind.Relative)).Stream); 
        LoopClip(sound);
    }


    private void button3_Click(object sender, RoutedEventArgs e)
    {
        PlaySound("sound3.wav");
    }

}

The above example assumes your sound files are set with Build Action = Content and are in the top level directory.