1.调用：

UserList = UserList.ToList().Intersect(userIDList, new MyUserComparer()).AsQueryable();

2.须要重写的方法：

public class MyUserComparer : IEqualityComparer<MyUser>

    {

        public bool Equals(MyUser x, MyUser y)

        {

            //throw new NotImplementedException();

            return x.UserID == y.UserID;

        }

        public int GetHashCode(MyUser obj)

        {

            return obj.ToString().GetHashCode();

        }

    }