silverlight中鼠标放在对象的提示事件

 <Rectangle x:Name="toolTip" Grid.Column="0"  Grid.Row="1" Fill="White"  Width="100" Height="100">
            <ToolTipService.ToolTip>
                <TextBlock>这里是toolTip！</TextBlock>
            </ToolTipService.ToolTip>
</Rectangle>

string tip = "这里是toolTip！";
toolTip.SetValue(ToolTipService.ToolTipProperty, tip);

<!--xaml里面矩形的定义-->
<Rectangle x:Name="toolTip" Grid.Column="0"  Grid.Row="1" Fill="White"  Width="100" Height="100">       
</Rectangle>

 <Rectangle x:Name="toolTip"  Grid.Column="0"  Grid.Row="1" Fill="White"  Width="100" Height="100" MouseLeave="toolTip_MouseLeave" MouseMove="toolTip_MouseMove">       
</Rectangle>
<Popup x:Name="tip">
        <TextBlock Foreground="Red" Text="这里是Popup"/>
        <!--<Rectangle Fill="DeepSkyBlue" Width="60" Height="40" />-->
 </Popup>

 private void toolTip_MouseLeave(object sender, MouseEventArgs e)
        {
            this.tip.IsOpen = false;  
        }

private void toolTip_MouseMove(object sender, MouseEventArgs e)
        {
            this.tip.IsOpen = true; 
            this.tip.HorizontalOffset = e.GetPosition(null).X + 20; 
            this.tip.VerticalOffset = e.GetPosition(null).Y - 20; 
        }