C# 如何在Windows8中使用MediaElement更改视频的位置？

目前我在代码中这样做

 playbackElement1.AutoPlay = true;
 playbackElement1.SetSource(stream, this.m_recordStorageFile.FileType);
 playbackElement1.Position = new TimeSpan(0, 0, 0, 0, 5000);
 playbackElement1.Play();

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它不工作，检查超过5秒的视频。

有两个问题。首先，只能在加载介质后设置位置，这是由处理事件决定的。第二，并非所有媒体都是可搜索的。打电话查一下。使用类似于：

playbackElement1.AutoPlay = true;
// Will fire after the media has loaded
playbackElement1.MediaOpened += (source, args) =>
{
    MediaElement player = (MediaElement) source;
    if (player.CanSeek)
    {
        player.Position = new TimeSpan(0, 0, 0, 0, 5000);   
    }
}                     
playbackElement1.SetSource(stream, this.m_recordStorageFile.FileType);

---

加载后，使用属性查看媒体长度，如果需要，使用和属性将其转换为时间跨度。

简而言之，您需要在媒体元素下添加一个滑块，就像在任何视频播放器中一样。。。 -滑块将更新播放器的当前位置 -计时器将每隔300毫秒用当前播放机位置更新滑块

代码：

<Slider x:Name="videoSlider" Thumb.DragStarted="videoSlider_DragStarted" Thumb.DragCompleted="videoSlider_DragCompleted" Margin="10,0,10,30" Height="18" VerticalAlignment="Bottom"/>

<MediaElement x:Name="videoPlayer" Margin="4,59,152,53" Volume=".5" MediaOpened="videoPlayer_MediaOpened"> 

         public partial class MainWindow : Window
         {  
               bool isSeekingMedia = false;
               DispatcherTimer seeker;   // the timer to update the Slider
               public MainWindow()
               {
                    InitializeComponent();
                    player = new MediaPLayer();
                    IsPlaying(false);
                    seeker = new DispatcherTimer();
                    seeker.Interval = TimeSpan.FromMilliseconds(200);
                    seeker.Tick += Seeker_Tick;
        }
    ///Seeker_Tick will update the Slider position while the video is playing
                private void Seeker_Tick(object sender, EventArgs e)
                {
                    try
                    {
                        MediatimeCounter.Content = String.Format("{0:hh}:{0:mm}:{0:ss}/{1:hh}:{1:mm}:{1:ss}", videoPlayer.Position, videoPlayer.NaturalDuration.TimeSpan);
                        if (!isSeekingMedia)
                        {
                            videoSlider.Value = videoPlayer.Position.TotalSeconds;
                        }
                    }
                    catch (Exception ex) { }
                }


//This code is going to set Seeking to true to avoid playing the video if the user is changing the slider position... it kinda causes a performance issue.. so it's better to update the video position once the slider dragging event is completed.
private void videoSlider_DragStarted(object sender, RoutedEventArgs e)
    {
        isSeekingMedia = true;
    }

//and this code is to update the video position based on the slider value.
private void videoSlider_DragCompleted(object sender, RoutedEventArgs e)
    {
        if (videoPlayer.Source != null)
        {
            isSeekingMedia = false;
            this.videoPlayer = player.SeekVideo(videoPlayer, videoSlider.Value);
        }
    }