SilverLight实现变化Ellipse大小和鼠标离开颜色

xaml

<UserControl
    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:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls" x:Class="SilverlightApplication1.MainPage"
    mc:Ignorable="d"
    d:DesignHeight="800" d:DesignWidth="800" Width="800">
<Grid x:Name="Lay" Background="White" >
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="0*"/>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>
    <Slider x:Name="MySlider" Width="500" Margin="16,0,35,74" RenderTransformOrigin="0.5,0.5" Grid.Column="1"  Maximum="200" VerticalAlignment="Bottom" ValueChanged="MySlider_ValueChanged">
        <Slider.RenderTransform>
            <TransformGroup>
                <ScaleTransform ScaleY="-1"/>
                <SkewTransform/>
                <RotateTransform/>
                <TranslateTransform/>
            </TransformGroup>
        </Slider.RenderTransform>
    </Slider>
    <Ellipse x:Name="MyEllipse" Grid.Column="1" Fill="#FFF4F4F5"  Margin="68,84,129,186" Stroke="Black" Width="200" Height="200" MouseEnter="MyEllipse_MouseEnter" MouseLeave="MyEllipse_MouseLeave" />
    </Grid>
</UserControl>

cs

 public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            MySlider.ValueChanged+=new RoutedPropertyChangedEventHandler<double>(MySlider_ValueChanged);
        }

       
     
        

        //给MySlider_ValueChanged 注册事件
        
        
        private void MySlider_ValueChanged(object sender, System.Windows.RoutedPropertyChangedEventArgs<double> e)
        {
            MyEllipse.Width=MySlider.Value;
            MyEllipse.Height=MySlider.Value;
        }

        private void MyEllipse_MouseEnter(object sender, System.Windows.Input.MouseEventArgs e)
        {
            MyEllipse.Fill=new SolidColorBrush(Colors.Red);
        }

        private void MyEllipse_MouseLeave(object sender, MouseEventArgs e)
        {
            MyEllipse.Fill=new SolidColorBrush(Colors.Blue);

        }
    }
}