//深拷贝对象

 /// <summary>
        /// 深拷贝对象：循环List是直接改变当前对象的值,所以如果需要改变值且不动到当前list需要深拷贝,  因为是引用类型最终都是指向一个内存地址
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="original"></param>
        /// <returns></returns>
        private static T DeepCopy<T>(T original)
        {
            return (T)JsonConvert.DeserializeObject(JsonConvert.SerializeObject(original), original.GetType());
        }

//求两个List<实体>之间的差集

    List<A> A = new List<A>();

    List<B> B= new List<B>();


   public class AEquality : IEqualityComparer<A>
    {
        public bool Equals(A x, A y)
        {
　　　　　　return x.Id == y.Id && x.Name == y.Name 
        }
        public int GetHashCode(A obj)
        {
            return (obj == null) ? 0 : obj.ToString().GetHashCode();
        }

    }

 var except = A.Except(B, new AEquality()).ToList();
            if (except.Count() > 0) throw JNPFException.Oh("存在差集");

//C类是A类的子类 可直接使用AEquality
如下

 var except = C.Except(B, new AEquality()).ToList();
            if (except.Count() > 0) throw JNPFException.Oh("存在差集");