为所有类型扩展一个深拷贝方法

/// <summary>
        /// 深拷贝对象副本
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="obj"></param>
        /// <returns></returns>
         public static T DeepClone<T>(this T obj) {
            System.Runtime.Serialization.Formatters.Binary.BinaryFormatter formatter = new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            T copy=default(T);
            try {
                formatter.Serialize(ms, obj);
                ms.Seek(0, System.IO.SeekOrigin.Begin);
                copy = (T)formatter.Deserialize(ms);
            } catch (Exception ex) {
                throw new Exception("深拷贝对象实例出错。", ex);
            } finally {
                ms.Close();
            }
            return copy;
        }