控制Storyboard播放zz

 <Grid Width="300" Height="460">
         <Grid.RowDefinitions>
             <RowDefinition Height="*"/>
             <RowDefinition Height="60"/>
             <RowDefinition Height="100"/>
         </Grid.RowDefinitions>
         <Grid.Triggers>
             <EventTrigger SourceName="btnStart" RoutedEvent="Button.Click">
                 <BeginStoryboard x:Name="myImageBStoryboard"  >
                     <Storyboard CurrentTimeInvalidated="Storyboard_CurrentTimeInvalidated">
                         <DoubleAnimation Storyboard.TargetName="myImageB" Storyboard.TargetProperty="Opacity" From="1" To="0" Duration="00:00:05">

                         </DoubleAnimation>
                     </Storyboard>
                 </BeginStoryboard>
             </EventTrigger>
             <EventTrigger SourceName="btnPause" RoutedEvent="Button.Click">
                 <PauseStoryboard BeginStoryboardName="myImageBStoryboard"></PauseStoryboard>
             </EventTrigger>
             <EventTrigger SourceName="btnResume" RoutedEvent="Button.Click">
                 <ResumeStoryboard BeginStoryboardName="myImageBStoryboard"></ResumeStoryboard>
             </EventTrigger>
             <EventTrigger SourceName="btnStop" RoutedEvent="Button.Click">
                 <StopStoryboard BeginStoryboardName="myImageBStoryboard"></StopStoryboard>
             </EventTrigger>
             <EventTrigger SourceName="btnMiddle" RoutedEvent="Button.Click">
                 <SeekStoryboard BeginStoryboardName="myImageBStoryboard" Offset="00:00:02">
                 </SeekStoryboard>
             </EventTrigger>
         </Grid.Triggers>
         <Grid Grid.Row="0" Grid.Column="0"  >
             <Image x:Name="myImageA" Source="Images/A.jpg"  Height="300" Width="300" Stretch="Fill"></Image>
             <Image x:Name="myImageB" Source="Images/B.jpg"   Height="300" Width="300"  Stretch="Fill" ></Image>
         </Grid>
         <StackPanel Grid.Row="1" Grid.Column="0" Orientation="Horizontal">
             <Button x:Name="btnStart" Content="Start" Width="50" Height="40"  Margin="3" ></Button>
             <Button x:Name="btnPause" Content="Pause" Width="50" Height="40" Margin="3" ></Button>
             <Button x:Name="btnResume" Content="Resume" Width="50" Height="40" Margin="3" ></Button>
             <Button x:Name="btnStop" Content="Stop" Width="50" Height="40" Margin="3" ></Button>
             <Button x:Name="btnMiddle" Content="SeekToMiddle" Width="50" Height="40" Margin="3" ></Button>
         </StackPanel>
         <StackPanel Grid.Row="2" Grid.Column="0" Orientation="Vertical">
             <TextBlock x:Name="myTextBlock" FontSize="13" Foreground="Red"> </TextBlock>
             <ProgressBar x:Name="myProgressBar"  Height="35" Background="White" Width="300" >
                 <ProgressBar.Foreground>
                     <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                         <GradientStop Color="#FF4DF22F" Offset="0.505" />
                         <GradientStop Color="#FFEFF5F1" Offset="1" />
                         <GradientStop Color="#FFF8F8F8" Offset="0.013" />
                     </LinearGradientBrush>
                 </ProgressBar.Foreground>
             </ProgressBar>
         </StackPanel>
     </Grid>

 public partial class MainWindow : Window
     {
         public MainWindow()
         {
             InitializeComponent();
         }

         private void Storyboard_CurrentTimeInvalidated(object sender, EventArgs e)
         {
             Clock storyboardClock = sender as Clock;
             if (storyboardClock.CurrentProgress != null)
             {
                 myTextBlock.Text = storyboardClock.CurrentTime.ToString();
                 myProgressBar.Value = (double)storyboardClock.CurrentProgress*;(注意这儿storyboardClock.CurrentProgres值范围是0至1)
                 System.Diagnostics.Debug.WriteLine(myProgressBar.Value);
             }
             else
             {
                 myProgressBar.Value = ;
                 myTextBlock.Text = "Stopped";
             }
         }
     }