Silverlight动画取消有关问题

Silverlight动画取消问题
鼠标移动到button上产生动画，当鼠标移除改button后怎么让动画停止呢？请高人指点！拜谢~~~~~~~
分不高聊表心意！

[解决办法]

C# code

                            <Trigger.EnterActions>                                <BeginStoryboard x:Name="beginAnimation">                                    <Storyboard RepeatBehavior="Forever" AutoReverse="True">                                        <DoubleAnimation Storyboard.TargetName="inPie"                                                     Storyboard.TargetProperty="Height"                                                     From="25" By="-10" Duration="0:0:1"/>                                        <DoubleAnimation Storyboard.TargetName="inPie"                                                     Storyboard.TargetProperty="Width"                                                     From="50" By="-20" Duration="0:0:1"/>                                        <DoubleAnimation Storyboard.TargetName="colorBrush"                                                    Storyboard.TargetProperty="Offset"                                                    From="0" By="1" Duration="0:0:1"/>                                    </Storyboard>                                </BeginStoryboard>                            </Trigger.EnterActions>                            <Trigger.ExitActions>                                <StopStoryboard BeginStoryboardName="beginAnimation"/>                            </Trigger.ExitActions>