class Program    {        static void Main(string[] args)        {            //持有接口的引用            List
     
       lists = new List
      
       ();            test te = new test() { user = new user() { name = "sa123", pwd = "123456" } };            lists.Add(te);            test te2 = new test() { user = new user() { name = "sa123", pwd = "123456" } };            if (!lists.Contains(te2))            {                lists.Add(te2);            }            Console.WriteLine(lists.Count);        }    }    //测试用接口    interface speak    {        void CanSpeak();    }    //实际测试类    class test : speak    {        public user user;        public void CanSpeak()        {            Console.WriteLine("sd");        }    }    //测试实体    class user    {        public string name = "";        public string pwd = "";    }