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.

Answer 2

You will need to play each sound from a separate thread.

What seems to be happening here is that the different Play method calls are interfering with each other since they are in the same thread.

Try just putting the background music in a separate thread and see if that solves the problem you mention in the question. If so, split the others out as well.