WPF设置动画在控件载入时就立刻执行

<YourControl.Triggers>
    <EventTrigger RoutedEvent="YourControl.Loaded"><!--这里是关键-->
        <BeginStoryboard>
          <Storyboard>
            <DoubleAnimation Storyboard.TargetProperty="Width" From="0" To="150" Duration="0:0:5" />
            <DoubleAnimation Storyboard.TargetProperty="Height" From="0" To="100" Duration="0:0:5" />
          </Storyboard>
        </BeginStoryboard>
    </EventTrigger>
</YourControl.Triggers>