用WPF媒体元素一个接一个地播放2个时间线

问题描述：

我试图在开始播放5秒钟的第一首歌曲，并在6秒钟后通过使用MediaTimeLine和故事板播放第二首歌曲10秒钟。

这里是代码，只需打开一个新的WPF应用程序并复制XAML和代码以重现它。哦，一定要改变路径2首歌曲在你的机器有本地..

<Window x:Class="WpfApp1.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:local="clr-namespace:WpfApp1" 
    mc:Ignorable="d" 
    Title="MainWindow" Height="350" Width="525"> 
<Grid> 
    <MediaElement Name="MediaElementObject1" /> 
    <Button Width="100" Height="100" Margin="26,48,391,171" Click="Button_Click"></Button> 
</Grid>

using System; 
using System.Windows; 
using System.Windows.Media; 
using System.Windows.Media.Animation; 

namespace WpfApp1 
{ 
    /// <summary> 
    /// Interaction logic for MainWindow.xaml 
    /// </summary> 
    public partial class MainWindow : Window 
    { 

     private readonly Storyboard animation = new Storyboard(); 

     public MainWindow() 
     { 
      InitializeComponent(); 

      var mediaUri1 = new Uri(@"C:\MediaExamplesForWork\Sting - Sting At The Movies - 07 - Shape OF My Heart (Leon & Three Of Hearts).mp3"); 
      var mediaUri2 = new Uri(@"C:\MediaExamplesForWork\Desireless - Voyage Voyage.mp3"); 
      animation.Duration = TimeSpan.FromSeconds(20); 

      var timeline1 = new MediaTimeline 
      { 
       Name = "a1", 
       BeginTime = TimeSpan.Zero, 
       Duration = TimeSpan.FromSeconds(5), 
       Source = mediaUri1, 
       FillBehavior = FillBehavior.HoldEnd 
      }; 
      Storyboard.SetTarget(timeline1, MediaElementObject1); 
      animation.Children.Add(timeline1); 

      var timeline2 = new MediaTimeline 
      { 
       Name = "a2", 
       BeginTime = TimeSpan.FromSeconds(6), 
       Duration = TimeSpan.FromSeconds(10), 
       Source = mediaUri2, 
       FillBehavior = FillBehavior.HoldEnd 
      }; 
      Storyboard.SetTarget(timeline2, MediaElementObject1); 
      animation.Children.Add(timeline2); 

      animation.Begin();  
     } 

     private void Button_Click(object sender, RoutedEventArgs e) 
     { 
      animation.SeekAlignedToLastTick(TimeSpan.FromSeconds(2)); 
     } 
    } 
}

你会发现第一首歌曲将无法播放，第二个会玩。如果您评论第二首歌曲 - 第一首歌曲将播放。

如何解决这个问题，所以两个将根据示例代码中已经设置的开始时间和持续时间播放？

答

媒体元素似乎不可能处理两个媒体时间线。

我不得不添加，我不喜欢其他媒体元素..但是这是我的最终解决这个问题..

<Window x:Class="WpfApp1.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:local="clr-namespace:WpfApp1" 
    mc:Ignorable="d" 
    Title="MainWindow" Height="350" Width="525"> 
<Grid> 
    <MediaElement Name="MediaElementObject1" /> 
    <MediaElement Name="MediaElementObject2" /> 
    <Button Width="100" Height="100" Margin="26,48,391,171" Click="Button_Click"></Button> 
</Grid>

using System; 
using System.Windows; 
using System.Windows.Media; 
using System.Windows.Media.Animation; 

namespace WpfApp1 
{ 
/// <summary> 
/// Interaction logic for MainWindow.xaml 
/// </summary> 
public partial class MainWindow : Window 
{ 

    private readonly Storyboard animation = new Storyboard(); 

    public MainWindow() 
    { 
     InitializeComponent(); 

     var mediaUri1 = new Uri(@"C:\MediaExamplesForWork\Sting - Sting At The Movies - 07 - Shape OF My Heart (Leon & Three Of Hearts).mp3"); 
     var mediaUri2 = new Uri(@"C:\MediaExamplesForWork\Desireless - Voyage Voyage.mp3"); 

     animation.Duration = TimeSpan.FromSeconds(20); 


     var timeline1 = new MediaTimeline 
     { 
      Name = "a1", 
      BeginTime = TimeSpan.Zero, 
      Duration = TimeSpan.FromSeconds(5), 
      Source = mediaUri1, 
      FillBehavior = FillBehavior.HoldEnd 
     }; 
     Storyboard.SetTarget(timeline1, MediaElementObject1); 
     animation.Children.Add(timeline1); 


     var timeline2 = new MediaTimeline 
     { 
      Name = "a2", 
      BeginTime = TimeSpan.FromSeconds(6), 
      Duration = TimeSpan.FromSeconds(10), 
      Source = mediaUri2, 
      FillBehavior = FillBehavior.HoldEnd 
     }; 
     Storyboard.SetTarget(timeline2, MediaElementObject2); 
     animation.Children.Add(timeline2); 

     animation.Begin(); 

    } 

    private void Button_Click(object sender, RoutedEventArgs e) 
    { 
     animation.SeekAlignedToLastTick(TimeSpan.FromSeconds(13)); 
    } 
} 
}

用WPF媒体元素一个接一个地播放2个时间线

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