Silverlight 3：事件触发器认为属性超出范围

我想在鼠标进入时使网格不透明。所以，我试图抓住MouseEnter事件和动画Opactity财产Silverlight 3：事件触发器认为属性超出范围

<Grid Opacity="0.1" Name="myGrid" > 
      <Grid.Triggers> 
       <EventTrigger RoutedEvent="Grid.MouseEnter" > 
        <BeginStoryboard> 
         <Storyboard> 
          <DoubleAnimation From="0.1" To="1" Duration="00:00:01" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="myGrid"/> 
         </Storyboard> 
        </BeginStoryboard> 
       </EventTrigger> 
      </Grid.Triggers> 
    </Grid>

但在InitializeComponent认为Grid.MouseEnter属性超出范围。我做错了什么？

来源

2011-03-17 Andrew Florko