根据Content获取到ItemsControl中对应的Item

        /// <summary>
        /// 根据控件的值获取到对应的Item
        /// </summary>
        /// <typeparam name="T">最终获取到Item的具体类型</typeparam>
        /// <param name="element">The element.</param>
        /// <param name="content">The content.</param>
        /// <returns></returns>
        public static T FindItemByContent<T>(this ItemsControl element, object content) where T : ItemsControl
        {
            ItemCollection items = element.Items;
            ItemContainerGenerator itemContainerGenerator = element.ItemContainerGenerator;
            if (items == null) return null;
            var item = (T)itemContainerGenerator.ContainerFromItem(content);
            if (item != null)
                return item;
            foreach (var i in items)
            {
                if (i.Equals(content)) continue;
                item = (T)itemContainerGenerator.ContainerFromItem(i);
                if (item == null) continue;
                item = FindItemByContent<T>(item, content);//递归
                if (item != null)
                    return item;
            }
            return null;
        }