使用Linq查找重复

 namespace RemoveTheSame
 {
     class Program
     {
         static void Main(string[] args)
         {
             List<User> list = new List<User>()
             {
                 new User{Id=,Name="user1",Pwd=""},
                 new User{Id=,Name="user1",Pwd=""},
                 new User{Id=,Name="user2",Pwd=""}
             };
             GetTheSame(list, out string tkey);
             Console.WriteLine($"The Same is {tkey}");
             Console.ReadKey();
         }
         public static void GetTheSame(List<User> listOld, out string tkey/*,out User user*/)
         {
             tkey = null;
             var result = from x in listOld
                          group x by x.Name into g
                          where g.Count() >
                          select g;
             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; }

     }
 }

其实就是一行代码解决的问题~

list.GroupBy(x => x.Name).Where(x => x.Count() > ).ToList().ForEach(x => Console.WriteLine(x.Key));