在Xamarin窗体中打开Swipe时，如何更改swipe View内容的不透明度？

<SwipeView>
    <SwipeView.Content>
        <!-- 这里放置需要进行滑动操作的内容 -->
    </SwipeView.Content>
</SwipeView>

private void OnSwipeStarted(object sender, SwipeStartedEventArgs e)
{
    SwipeItem swipeItem = e.SwipeItem;
    View contentView = swipeItem.ContentView;
    contentView.Opacity = 0.5; // 设置不透明度为0.5
}

private void OnSwipeEnded(object sender, SwipeEndedEventArgs e)
{
    SwipeItem swipeItem = e.SwipeItem;
    View contentView = swipeItem.ContentView;
    contentView.Opacity = 1.0; // 恢复不透明度为1.0
}

<SwipeView SwipeStarted="OnSwipeStarted" SwipeEnded="OnSwipeEnded">
    <SwipeView.Content>
        <!-- 这里放置需要进行滑动操作的内容 -->
    </SwipeView.Content>
</SwipeView>