Silverlight2 实例之 音频播放器【附源码下载】

【完整实例源码下载】众所周知Silverlight2对于音视频媒体也提供了很好的支持，本篇就音频部分做一个播放器实例。

本例实现的是播放器最基本的功能，大家可通过该例体会一下Silverlight2对音频的控制。
本例参考自《Pro Silverlight 2 in C# 2008》CHAPTER 10 SOUND, VIDEO, AND DEEP ZOOM

先上个效果图看看：

XAML Code：

1. <UserControl x:Class="MusicPlayer.Page" 
2.     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
3.     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
4.     Height="250" Width="200"> 
5.     <Grid Margin="20"> 
6.         <Grid.Background> 
7.             <LinearGradientBrush StartPoint="0,0" EndPoint="0,1"> 
8.                 <GradientStop Color="Gold" Offset="0"></GradientStop> 
9.                 <GradientStop Color="White" Offset="0.5"></GradientStop> 
10.                 <GradientStop Color="Gold" Offset="1"></GradientStop> 
11.             </LinearGradientBrush> 
12.         </Grid.Background> 
13.         <Grid.RowDefinitions> 
14.             <RowDefinition Height="Auto"></RowDefinition> 
15.             <RowDefinition Height="Auto"></RowDefinition> 
16.             <RowDefinition Height="Auto"></RowDefinition> 
17.             <RowDefinition Height="Auto"></RowDefinition> 
18.             <RowDefinition Height="Auto"></RowDefinition> 
19.         </Grid.RowDefinitions> 
20.  
21.         <!--媒体组件--> 
22.         <MediaElement x:Name="media" AutoPlay="False" Source="test.mp3"   
23.                       MediaOpened="media_MediaOpened"  
24.                       MediaFailed="media_MediaFailed" 
25.                       MediaEnded="media_MediaEnded"  
26.                       CurrentStateChanged="media_CurrentStateChanged"> 
27.         </MediaElement> 
28.         <StackPanel Orientation="Horizontal"> 
29.             <!--播放键--> 
30.             <Button Click="cmdPlay_Click" Padding="15" Margin="5"> 
31.                 <StackPanel> 
32.                     <Polygon Points="0,0 0,10 10,5" Fill="Green"></Polygon> 
33.                 </StackPanel> 
34.             </Button> 
35.             <!--停止键--> 
36.             <Button Click="cmdStop_Click" Padding="15" Margin="5"> 
37.                 <StackPanel> 
38.                     <Rectangle Height="10" Width="10" Fill="Red"></Rectangle> 
39.                 </StackPanel> 
40.             </Button> 
41.             <!--暂停键--> 
42.             <Button Click="cmdPause_Click" Padding="15" Margin="5"> 
43.                 <StackPanel Orientation="Horizontal"> 
44.                     <Rectangle Margin="1" Height="10" Width="3" Fill="Blue"></Rectangle> 
45.                     <Rectangle Margin="1" Height="10" Width="3" Fill="Blue"></Rectangle> 
46.                 </StackPanel> 
47.             </Button> 
48.         </StackPanel> 
49.  
50.         <Grid Grid.Row="1" Margin="0,10,0,0"> 
51.             <Grid.RowDefinitions> 
52.                 <RowDefinition Height="Auto"></RowDefinition> 
53.                 <RowDefinition Height="Auto"></RowDefinition> 
54.                 <RowDefinition Height="Auto"></RowDefinition> 
55.             </Grid.RowDefinitions> 
56.             <Grid.ColumnDefinitions> 
57.                 <ColumnDefinition Width="Auto"></ColumnDefinition> 
58.                 <ColumnDefinition></ColumnDefinition> 
59.             </Grid.ColumnDefinitions> 
60.  
61.             <!--音量调节按钮--> 
62.             <TextBlock Margin="5" Text="Volume: "></TextBlock> 
63.             <Slider x:Name="sliderVolume" Grid.Column="1"  Minimum="0" Maximum="1" Value="0.5" 
64.                     ValueChanged="sliderVolume_ValueChanged"></Slider> 
65.             <!--平衡调节按钮--> 
66.             <TextBlock Grid.Row="1" Margin="5" Text="Balance: "></TextBlock> 
67.             <Slider x:Name="sliderBalance" Grid.Row="1" Grid.Column="1" Minimum="-1" Maximum="1" 
68.                     ValueChanged="sliderBalance_ValueChanged"></Slider> 
69.             <!--播放进度调节按钮--> 
70.             <TextBlock Grid.Row="2" Margin="5" Text="Seek To: "></TextBlock> 
71.             <Slider x:Name="sliderPosition" Minimum="0" Grid.Column="1" Grid.Row="2" 
72.                     ValueChanged="sliderPosition_ValueChanged"></Slider> 
73.             <!--播放进度条--> 
74.             <Slider x:Name="sliderPositionBackground" Minimum="0" Grid.Column="1" Grid.Row="2"  
75.                     IsHitTestVisible="False" Opacity="0.5"> 
76.             </Slider> 
77.         </Grid> 
78.  
79.         <!--循环播放选项--> 
80.         <CheckBox x:Name="chkLoop" Grid.Row="2" Margin="5,5,5,5" Content="Loop"></CheckBox> 
81.         <!--静音选项--> 
82.         <CheckBox x:Name="chkMute" Grid.Row="3" Margin="5,0" Content="Mute" Click="chkMute_Click"></CheckBox> 
83.         <!--播放状态提示--> 
84.         <TextBlock x:Name="lblStatus" Grid.Row="4" Margin="10" HorizontalAlignment="Center"></TextBlock> 
85.     </Grid> 
86. </UserControl> 

C# Code：

1. using System; 
2. using System.Collections.Generic; 
3. using System.Windows; 
4. using System.Windows.Controls; 
5. using System.Windows.Media; 
6. using System.Windows.Media.Animation; 
7. using System.Windows.Threading; 
8.  
9. namespace MusicPlayer 
10. { 
11.     public partial class Page : UserControl 
12.     { 
13.         public Page() 
14.         { 
15.             InitializeComponent(); 
16.             //设置计时器精确度 
17.             timer.Interval = TimeSpan.FromSeconds(0.1); 
18.             //装载计时器 
19.             timer.Tick += timer_Tick; 
20.         } 
21.  
22.         //停止播放 
23.         public void mediaStop() 
24.         { 
25.             //将进度调节按钮与进度条归零 
26.             sliderPosition.Value = 0; 
27.             sliderPositionBackground.Value = 0; 
28.             //停止播放 
29.             media.Stop(); 
30.             timer.Stop(); 
31.         } 
32.  
33.         private void timer_Tick(object sender, EventArgs e) 
34.         { 
35.             lblStatus.Text = media.Position.ToString().TrimEnd(new char[] { '0' }); 
36.             //使播放进度条跟随播放时间移动 
37.             sliderPositionBackground.Value = media.Position.TotalSeconds; 
38.         } 
39.  
40.         //计时器 
41.         private DispatcherTimer timer = new DispatcherTimer(); 
42.  
43.         //播放键 
44.         private void cmdPlay_Click(object sender, RoutedEventArgs e) 
45.         { 
46.             //判断播放器是否处于暂停状态 
47.             if (sliderPositionBackground.Value != 0) 
48.             { 
49.                 //处于暂停状态则继续播放 
50.                 media.Position = TimeSpan.FromSeconds(sliderPositionBackground.Value); 
51.                 media.Play(); 
52.                 timer.Start(); 
53.             } 
54.             else 
55.             { 
56.                 //处于停止状态则开始播放 
57.                 media.Stop(); 
58.                 media.Play(); 
59.                 timer.Start(); 
60.             } 
61.         } 
62.  
63.         //暂停键 
64.         private void cmdPause_Click(object sender, RoutedEventArgs e) 
65.         { 
66.             media.Pause(); 
67.             timer.Stop(); 
68.         } 
69.  
70.         //停止键 
71.         private void cmdStop_Click(object sender, RoutedEventArgs e) 
72.         { 
73.             mediaStop(); 
74.         } 
75.          
76.         //播放器打开 
77.         private void media_MediaOpened(object sender, RoutedEventArgs e) 
78.         { 
79.             media.Stop(); 
80.             //将播放进度调节按钮和播放进度条的长度设为音频时长 
81.             sliderPosition.Maximum = media.NaturalDuration.TimeSpan.TotalSeconds; 
82.             sliderPositionBackground.Maximum = media.NaturalDuration.TimeSpan.TotalSeconds; 
83.         } 
84.  
85.         //播放进度调节按钮 
86.         private void sliderPosition_ValueChanged(object sender, RoutedEventArgs e) 
87.         { 
88.             //使进度条跟随调节按钮移动 
89.             sliderPositionBackground.Value = sliderPosition.Value; 
90.             //从调节位置播放 
91.             media.Stop(); 
92.             media.Position = TimeSpan.FromSeconds(sliderPosition.Value); 
93.             media.Play(); 
94.             timer.Start(); 
95.         } 
96.  
97.         //音量调节按钮 
98.         private void sliderVolume_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e) 
99.         { 
100.             if (media != null) media.Volume = sliderVolume.Value; 
101.         } 
102.  
103.         //平衡调节按钮 
104.         private void sliderBalance_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e) 
105.         { 
106.             media.Balance = sliderBalance.Value; 
107.         } 
108.  
109.         //静音选项 
110.         private void chkMute_Click(object sender, RoutedEventArgs e) 
111.         { 
112.             media.IsMuted = (bool)chkMute.IsChecked; 
113.         } 
114.  
115.         //获取错误提示 
116.         private void media_MediaFailed(object sender, ExceptionRoutedEventArgs e) 
117.         { 
118.             lblStatus.Text = e.ErrorException.Message; 
119.         } 
120.  
121.         //播放结束 
122.         private void media_MediaEnded(object sender, RoutedEventArgs e) 
123.         { 
124.             //判断是否需要循环播放 
125.             if ((bool)chkLoop.IsChecked) 
126.             { 
127.                 //循环播放 
128.                 media.Position = TimeSpan.Zero; 
129.                 media.Play(); 
130.             } 
131.             else 
132.             { 
133.                 //停止播放 
134.                 mediaStop(); 
135.             } 
136.         } 
137.  
138.         //获取播放状态 
139.         private void media_CurrentStateChanged(object sender, RoutedEventArgs e) 
140.         { 
141.             //在Textblock中显示播放状态 
142.             lblStatus.Text = media.CurrentState.ToString(); 
143.         } 
144.     } 
145. }