wpf Button 动态改变效果

<Button  x:Name="LearnMore"  Grid.Row="6"  HorizontalAlignment="Left" VerticalAlignment="Top" Click="go_webSite" >

<Button.Template>

<ControlTemplate TargetType="Button">

<Border Background="{TemplateBinding Button.Background}"  Cursor="Hand" CornerRadius="21" Height="42" Width="160">

<StackPanel Orientation="Horizontal" HorizontalAlignment="Center">

<TextBlock  Height="25" VerticalAlignment="Center" Margin="0,4,0,0" Width="73" Foreground="#FFFFFF" FontSize="18"   TextAlignment="Center"  >了解更多</TextBlock>

<Image Width="14" Margin="8,2,0,0" Height="12" Source="/Imgs/arrow.png" />

</StackPanel>

</Border>

<ControlTemplate.Triggers>

<Trigger  Property="Button.IsMouseOver"  Value="True">

<Setter Property="Button.Background" Value="#0096D6" />

</Trigger>

<Trigger  Property="Button.IsMouseOver"  Value="false">

<Setter Property="Button.Background" Value="#177BBF" />

</Trigger>

<Trigger  Property="Button.IsPressed"  Value="true">

<Setter Property="Button.Background" Value="#2285C9" />

</Trigger>

</ControlTemplate.Triggers>

</ControlTemplate>

</Button.Template>

</Button>