List & lt; object & gt; Distinct () deduplication, objectdistinct

List <object> Distinct () deduplication, objectdistinct

Sometimes we deduplicate the data in a list <T> set. C # provides a Distinct () method that can be clicked directly. If T in list <T> is a custom object, the Distinct effect cannot be achieved for the set Distinct. We need to define a new de-duplicated class and inherit the IEqualityComparer interface to override the Equals and GetHashCode methods. The following Demo

 1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4  5 namespace MyTestCode 6 { 7     /// <summary> 8     /// Description of DistinctDemo. 9     /// </summary>10     public class DistinctDemo11     {12         private static List<Student> list;13         public DistinctDemo()14         {15         }16         17         public static void init()18         {19             list = new List<Student>{20                 new Student{21                     Id=1,22                     Name="xiaoming",23                     Age=2224                 },25                 new Student{26                     Id=2,27                     Name="xiaohong",28                     Age=2329                 },30                 new Student{31                     Id=2,32                     Name="xiaohong",33                     Age=2334                 },35             };36         }37         38         public void Display()39         {40             list = list.Distinct(new ListDistinct()).ToList();41             foreach (var element in list) {42                 Console.WriteLine(element.Id +"/"+element.Name+"/"+element.Age);43             }44         }45         46     }47     48     public class Student49     {50         public int Id{get;set;}51         public string Name{get;set;}52         public int Age{get;set;}53     }54     55     public class ListDistinct : IEqualityComparer<Student>56     {57         public bool Equals(Student s1,Student s2)58         {59             return (s1.Name == s2.Name);60         }61         62         public int GetHashCode(Student s)63         {64             return s==null?0:s.ToString().GetHashCode();65         }66     }67 }