Silverlight 2提示“值不在预期的范围内”

悬赏园豆：50 [已关闭问题] 关闭于 2009-06-10 18:54

我在自定义控件中尝试将它添加至主页面的LayoutRoot中出错，代码如下：

Code
if (Application.Current.RootVisual is UserControl)
            {
                UserControl rootVisual = Application.Current.RootVisual as UserControl;
                PropertyInfo prop = rootVisual.GetType().GetProperty("Content", BindingFlags.NonPublic | BindingFlags.Instance);
                if (prop != null)
                {
                    UIElement content = prop.GetValue(this, null) as UIElement;
                    if (content is Panel)
                    {
                        Panel panel = content as Panel;
                        panel.Children.Add(this);
                    }
                }
            }