您是否将 UserControl 的背景设置为某些内容?如果没有，请尝试将其设置为背景=透明"，看看是否有效.如果它不起作用，您能否发布 UserControl 的 XAML 及其用法?

Did you have the Background of the UserControl set to something? If not, try setting it to "Background=Transparent" and see if that works. If it doesn't work, can you post the XAML for your UserControl, as well as the XAML for its usage?