WPF如何自定义ProgressBar滚动条样式

<Style TargetType="{x:Type ProgressBar}">
   <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
   <Setter Property="SnapsToDevicePixels" Value="True"/>
   <Setter Property="Height" Value="15"/>
   <Setter Property="Background" Value="#6fae5f"/>
   <Setter Property="FontSize" Value="10"/>
   <Setter Property="Padding" Value="5,0"/>
   <Setter Property="Template">
    <Setter.Value>
     <ControlTemplate TargetType="{x:Type ProgressBar}">
      <Grid Background="#00000000">
       <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
       </Grid.RowDefinitions>
       <VisualStateManager.VisualStateGroups>
        <VisualStateGroup x:Name="CommonStates">
         <VisualState x:Name="Determinate"/>
         <VisualState x:Name="Indeterminate">
          <Storyboard RepeatBehavior="Forever">
           <PointAnimationUsingKeyFrames Storyboard.TargetName="Animation" Storyboard.TargetProperty="(UIElement.RenderTransformOrigin)">
            <EasingPointKeyFrame KeyTime="0:0:0" Value="0.5,0.5"/>
            <EasingPointKeyFrame KeyTime="0:0:1.5" Value="1.95,0.5"/>
            <EasingPointKeyFrame KeyTime="0:0:3" Value="0.5,0.5"/>
           </PointAnimationUsingKeyFrames>
          </Storyboard>
         </VisualState>
        </VisualStateGroup>
       </VisualStateManager.VisualStateGroups>
       
       <Grid Height="{TemplateBinding Height}">
        <Border Background="#000000" CornerRadius="7.5" Opacity="0.05"/>
        <Border BorderBrush="#000000" BorderThickness="1" CornerRadius="7.5" Opacity="0.1"/>
        <Grid Margin="{TemplateBinding BorderThickness}">
         <Border x:Name="PART_Track"/>
         <Grid x:Name="PART_Indicator" ClipToBounds="True" HorizontalAlignment="Left" >
          <Grid.ColumnDefinitions>
           <ColumnDefinition x:Name="width1"/>
           <ColumnDefinition x:Name="width2" Width="0"/>
          </Grid.ColumnDefinitions>
          <Grid x:Name="Animation" RenderTransformOrigin="0.5,0.5">
           <Grid.RenderTransform>
            <TransformGroup>
             <ScaleTransform ScaleY="-1" ScaleX="1"/>
             <SkewTransform AngleY="0" AngleX="0"/>
             <RotateTransform Angle="180"/>
             <TranslateTransform/>
            </TransformGroup>
           </Grid.RenderTransform>
           <Border Background="{TemplateBinding Background}" CornerRadius="7.5">
            <Viewbox HorizontalAlignment="Left" StretchDirection="DownOnly" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="True">
             <TextBlock Foreground="#ffffff" SnapsToDevicePixels="True" FontSize="{TemplateBinding FontSize}" VerticalAlignment="Center" Text="{Binding RelativeSource={RelativeSource TemplatedParent},Path=Value,StringFormat={}{0}%}" RenderTransformOrigin="0.5,0.5">
              <TextBlock.RenderTransform>
               <TransformGroup>
                <ScaleTransform ScaleY="1" ScaleX="-1"/>
                <SkewTransform AngleY="0" AngleX="0"/>
                <RotateTransform Angle="0"/>
                <TranslateTransform/>
               </TransformGroup>
              </TextBlock.RenderTransform>
             </TextBlock>
            </Viewbox>
           </Border>
           <Border BorderBrush="#000000" BorderThickness="1" CornerRadius="7.5" Opacity="0.1"/>
          </Grid>
         </Grid>
        </Grid>
       </Grid>
      </Grid>
      <ControlTemplate.Triggers>
       
       <Trigger Property="IsEnabled" Value="False">
        <Setter Property="Background" Value="#c5c5c5"/>
       </Trigger>
       <Trigger Property="IsIndeterminate" Value="true">
        <Setter TargetName="width1" Property="Width" Value="0.25*"/>
        <Setter TargetName="width2" Property="Width" Value="0.725*"/>
       </Trigger>
      </ControlTemplate.Triggers>
     </ControlTemplate>
    </Setter.Value>
   </Setter>
  </Style>

<ProgressBar Height="15" Width="150" Value="40" Margin="10"/>