使用Linq查找重覆

 1 namespace RemoveTheSame
 2 {
 3     class Program
 4     {
 5         static void Main(string[] args)
 6         {
 7             List<User> list = new List<User>()
 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<User> listOld, out string tkey/*,out User user*/)
18         {
19             tkey = null;
20             var result = from x in listOld
21                          group x by x.Name into g
22                          where g.Count() > 1
23                          select g;
24             foreach (var item in result)
25             {
26                 tkey = item.Key;
27             }
28         }
29     }
30     public class User
31     {
32         public string Name { get; set; }
33         public int Id { get; set; }
34         public string Pwd { get; set; }
35 
36     }
37 }