前台代码：
<!--LayoutRoot 是包含所有页面内容的根网格-->
<Grid x:Name="LayoutRoot" Background="Transparent"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions><!--TitlePanel 包含应用程序的名称和页标题-->
<StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,17,0,28"> <TextBlock FontSize="25" x:Name="ApplicationTitle" Text="我的应用程序" Style="{StaticResource PhoneTextNormalStyle}"/> <TextBlock FontSize="60" x:Name="PageTitle" Text="播放MediaPlayer" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}" Width="486" /> </StackPanel><!--ContentPanel - 在此处放置其他内容-->
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0"> <Image Height="216" HorizontalAlignment="Left" Margin="35,48,0,0" Name="cover" Stretch="Fill" VerticalAlignment="Top" Width="401" /> <TextBox Height="72" HorizontalAlignment="Left" Margin="1,298,0,0" Name="SongName" Text="" VerticalAlignment="Top" Width="460" /> <Button Content="播放" Height="72" HorizontalAlignment="Left" Margin="6,409,0,0" Name="btn_play_music" VerticalAlignment="Top" Width="444" Click="btn_play_music_Click_1" /> <Button Content="停止" Height="72" HorizontalAlignment="Left" Margin="12,503,0,0" Name="btn_stop" VerticalAlignment="Top" Width="438" Click="btn_stop_Click_1" /></Grid>
</Grid>
后台代码：
namespace yinyuebofangqi
{ public partial class MainPage : PhoneApplicationPage { #region 成员声明 Song _playSong; //声明一个Song 类型的变量 bool _historyItemLaunch; const String _playSongKey = "playSong"; #endregion // Constructor public MainPage() { InitializeComponent(); _playSong = null; _historyItemLaunch = false;//声明一个Timer 使用线程运行 XNA internals 来自于微软XNA框架
DispatcherTimer dt = new DispatcherTimer(); dt.Interval = TimeSpan.FromMilliseconds(33); //使用委托调用逐帧调用 FrameworkDispatcher.Update(); dt.Tick += delegate { try { // 这个函数作用是更新各种XNA组件状态，并触发相应的事件,这个是必须的，否则会报异常 FrameworkDispatcher.Update();}
catch {throw;
} }; dt.Start();MediaPlayer.MediaStateChanged += new EventHandler<EventArgs>(MediaPlayer_MediaStateChanged);
}
/// <summary>
/// 当页面进入时调用 /// </summary> /// <param name="e"></param> protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e) { MediaLibrary library = new MediaLibrary(); if (NavigationContext.QueryString.ContainsKey(_playSongKey)) { String songToPlay = NavigationContext.QueryString[_playSongKey]; foreach (Song song in library.Songs) { if (0 == String.Compare(songToPlay, song.Name)) { _playSong = song; } } _historyItemLaunch = true; } else if (MediaPlayer.State == MediaState.Playing) { _playSong = MediaPlayer.Queue.ActiveSong; } else { Random rd = new Random(); if (library.Songs.Count > 0) { _playSong = library.Songs[rd.Next(library.Songs.Count)]; } else { SongName.Text = "no songs in library"; btn_play_music.IsEnabled = false; } } base.OnNavigatedTo(e); }void MediaPlayer_MediaStateChanged(object sender, EventArgs e)
{ switch (MediaPlayer.State) {case MediaState.Playing:
btn_play_music.IsEnabled = false; btn_stop.IsEnabled = true; break; case MediaState.Paused: case MediaState.Stopped: btn_play_music.IsEnabled = true; btn_stop.IsEnabled = false; break; } }/// <summary>
/// 为主窗体添加UI加载完成后的事件 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void PhoneApplicationPage_Loaded(object sender, RoutedEventArgs e) { PopulateSongMetaData(); setInitialButtonState(); if (_historyItemLaunch) { playSong(); } } /// <summary> /// 开始播放音乐 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> //private void btn_play_music_Click(object sender, RoutedEventArgs e) //{ // playSong(); //}/ <summary>
/ 停止播放音乐 / </summary> / <param name="sender"></param> / <param name="e"></param> //private void btn_stop_Click(object sender, RoutedEventArgs e) //{ // stopSong(); //}/// <summary>
/// 播放 /// </summary> private void playSong() { if (_playSong != null) { MediaPlayer.Play(_playSong); } } /// <summary> /// 停止 /// </summary> private void stopSong() { if (MediaState.Playing == MediaPlayer.State) { MediaPlayer.Stop(); } }/// <summary>
/// 使用图片读取图片封面 /// </summary> private void PopulateSongMetaData() { if (_playSong != null) { SongName.Text = _playSong.Name; Stream albumArtStream = _playSong.Album.GetAlbumArt(); if (albumArtStream == null) { StreamResourceInfo albumArtPlaceholder = Application.GetResourceStream(new Uri("ApplicationIcon.png", UriKind.Relative)); albumArtStream = albumArtPlaceholder.Stream; } BitmapImage albumArtImage = new BitmapImage(); albumArtImage.SetSource(albumArtStream); cover.Source = albumArtImage; } }/// <summary>
/// 初始化按钮 /// </summary> private void setInitialButtonState() { switch (MediaPlayer.State) {case MediaState.Playing:
btn_play_music.IsEnabled = false; btn_stop.IsEnabled = true; break; case MediaState.Paused: case MediaState.Stopped: btn_play_music.IsEnabled = true; btn_stop.IsEnabled = false; break; } }private void btn_play_music_Click_1(object sender, RoutedEventArgs e)
{ playSong(); }private void btn_stop_Click_1(object sender, RoutedEventArgs e)
{ stopSong(); }
}
}