xna中的声音问题

Question

我有两个主要页面GamePage（游戏中所有代码都在其中）和Mainpage（标题屏幕）。我想要做的是在标题画面上播放音乐（mainpage.xaml）

我尝试使用content.load方法，就像我在gamepage.xaml中所做的那样。但这不起作用，它提出null exception。我也尝试将其放在标题为MazeEscapePhoneSilveright的屏幕截图中，但是当我尝试运行它时;错误unexpected characters in the sound file出现了。

如何在mainpage.xaml上播放音乐，似乎没有尝试过：

Codebehind mainpage.xaml：

public partial class MainPage : PhoneApplicationPage
{
    // Constructor
    ContentManager contentManager;
    MediaElement player = null;
    Popup nameEntry = new Popup();
    bool gameMusic;
    bool mazeStart = true;
    TextBox txtNameEntry = new TextBox();

    SoundEffect theme_music;
    SoundEffectInstance theme_music_Instance;
    SoundEffect zap;
    SoundEffectInstance zapInstance;



    public MainPage()
    {
        InitializeComponent();
        //SharedGraphicsDeviceManager.Current.GraphicsDevice.SetSharingMode(true);


        //Plays the music through a mediaplayer, and a public boolean value.
        if (App.Current.Resources.Contains("mediaPlayer"))
        {
            player = App.Current.Resources["mediaPlayer"] as MediaElement;
            player.Source = new Uri("./MazeEscapePhoneSilverightLibContent/Media/magic_wav_file", UriKind.Relative);
        }

        gameMusic = ((App)Application.Current).gameMusic;

        if (gameMusic) player.Play();
    }

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        if (((App)Application.Current).gameMusic)
        {
            //theme_music = this.contentManager.Load<SoundEffect>("Media/magic_wav_file");
            //theme_music_Instance = theme_music.CreateInstance();


        }

    }

    //method runs when "Start Game" button is pressed
    private void btnStartGame_Click(object sender, RoutedEventArgs e)
    {
        if (gameMusic)
        {
            player.Play();
        }

        #region CREATE AND DISPLAY POP UP

        Border border = new Border();
        border.BorderBrush = new SolidColorBrush(Colors.White);
        border.BorderThickness = new Thickness(10);

        StackPanel myStackPanel = new StackPanel();
        myStackPanel.Background = new SolidColorBrush(Colors.Black);

        //Textblock containing the name you input and its properties.
        //txtNameEntry.Text = Microsoft.Phone.Info.DeviceExtendedProperties.GetValue("DeviceName").ToString();
        txtNameEntry.Text = "Player 1";
        txtNameEntry.Width = 350;
        txtNameEntry.Height = 100;
        txtNameEntry.MaxLength = 10;
        txtNameEntry.FontFamily = new FontFamily("Comis Sans MS");
        txtNameEntry.FontSize = 48.0;
        txtNameEntry.Foreground = new SolidColorBrush(Colors.Orange);
        txtNameEntry.Background = new SolidColorBrush(Colors.LightGray);
        txtNameEntry.BorderBrush = new SolidColorBrush(Colors.LightGray);

        //The ok button, which then allows you to procede into the game.
        Button btnNameEntryOK = new Button();
        btnNameEntryOK.Content = "Ok";
        btnNameEntryOK.Background = new SolidColorBrush(Colors.Orange);
        btnNameEntryOK.FontFamily = new FontFamily("Comic Sans Ms");
        btnNameEntryOK.FontSize = 25.0;
        btnNameEntryOK.Width = 180;
        btnNameEntryOK.Height = 70;
        btnNameEntryOK.Click += new RoutedEventHandler(btnNameEntryOK_Click);
        btnNameEntryOK.Margin = new Thickness(10);

        //Place these in the order you want them to be renderd to the screen.
        myStackPanel.Children.Add(txtNameEntry);
        myStackPanel.Children.Add(btnNameEntryOK); 
        border.Child = myStackPanel;
        nameEntry.Child = border;

        //set screen position of pop up 
        nameEntry.VerticalOffset = 100.0;
        nameEntry.HorizontalOffset = 50.0;

        //open pop up
        nameEntry.IsOpen = true;

        #endregion

        if (nameEntry.IsOpen == false && mazeStart == true)
        {
            player.Stop();
        }

    }

    void btnNameEntryOK_Click(object sender, RoutedEventArgs e)
    {
        ((App)Application.Current).playerName = txtNameEntry.Text;
        nameEntry.IsOpen = false;
        mazeStart = true;
        player.Stop();
        NavigationService.Navigate(new Uri("/GamePage.xaml", UriKind.Relative));

    }

    private void btnOptions_Click(object sender, RoutedEventArgs e)
    {
        nameEntry.IsOpen = false;
        NavigationService.Navigate(new Uri("/Options.xaml", UriKind.Relative));
    }

解决方案资源管理器的屏幕截图：