1 namespace RemoveTheSame 2 { 3     class Program 4     { 5         static void Main(string[] args) 6         { 7             List
       
         list = new List
        
         () 8             { 9                 new User{Id=1,Name="user1",Pwd="123"},10                 new User{Id=2,Name="user1",Pwd="123"},11                 new User{Id=3,Name="user2",Pwd="123"}12             };13             GetTheSame(list, out string tkey);14             Console.WriteLine($"The Same is {tkey}");15             Console.ReadKey();16         }17         public static void GetTheSame(List
         
           listOld, out string tkey/*,out User user*/)18         {19             tkey = null;20             var result = from x in listOld21                          group x by x.Name into g22                          where g.Count() > 123                          select g;24             foreach (var item in result)25             {26                 tkey = item.Key;27             }28         }29     }30     public class User31     {32         public string Name { get; set; }33         public int Id { get; set; }34         public string Pwd { get; set; }35 36     }37 }
         
        
       

 

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace 使用Linq查找重复{    class Program    {        static void Main(string[] args)        {            List
       
         list = new List
        
         ()            {                new User{Id=1,Name="user1",Pwd="123"},                 new User{Id=2,Name="user1",Pwd="123"},                 new User{Id=3,Name="user2",Pwd="123"}             };            string tkey = "";            GetTheSame(list, out tkey);            //Console.WriteLine($"The Same is {tkey}");            Console.ReadKey();        }        public static void GetTheSame(List
         
           listOld, out string tkey/*,out User user*/)        {            tkey = null;            var resulst = from x in listOld                          group x by x.Name into g                          select g;            var result = from x in listOld                         group x by x.Name into g        //根据 name 分组 返回 一个集合(集合中每个元素 又是一个集合)                         where g.Count() > 1         // 集合中每个 元素集合行数大于1的                         select g;     // g为  IGrouping
          
             类型            //g里面有多对       string  List
           
                        //string 为 key     每个 string 又继而对应一个集合  集合元素类型为User            //IGrouping
            
              //表示具有公共键的对象的集合。 foreach (var item in result) { tkey = item.Key; } } } public class User { public string Name { get; set; } public int Id { get; set; } public string Pwd { get; set; } }}