C# List去重的三种方法

class Program  
    {  
        static void Main(string[] args)  
        {  
            List<User> users = new List<User>();  
            users.Add(new User("张三", "啊啊啊"));  
            users.Add(new User("张三", "哈哈哈哈哈哈"));//重复项，去重后将删掉  
            users.Add(new User("李四", "忐忐忑忑通天塔"));  
  
            List<User>  List1 = users.Distinct().ToList();//通过User类的Equals实现去重  
            List<User>  List2 = users.Where((x,i)=>users.FindIndex(z=>z.name == x.name) == i).ToList();//Lambda表达式去重  
            List<User>  List3 = new List<User>();//通过循环方式去重  
            foreach(User user in users)  
            {  
                if( List3.Exists(x=>x.name==user.name) == false)  
                {  
                     List3.Add(user);  
                }  
            }  
  
            foreach(List<User> list in new Object[]{ List1, List2, List3})//打印出三个List的元素  
            {  
                Console.Write(" List:\r\n");  
                foreach(User u in list)  
                {  
                    Console.WriteLine("\t" + u.ToString());  
                }  
            }  
            Console.Read();  
        }  
    }  
  
    class User:IEquatable<User>//继承IEquatable接口，实现Equals方法。List就可以使用Distinct去重  
    {  
        public string name { get; set; }  
        string address;  
  
        public User(string _name, string _address)  
        {  
            name = _name;  
            address = _address;  
        }  
  
        public override string ToString()  
        {  
            return string.Format("name:{0},\taddress:{1}", name, address);  
        }  
  
        public bool Equals(User other)  
        {  
            return this.name == other.name;  
        }  
        public override int GetHashCode()  
        {  
            return name.GetHashCode();  
        }  
    }