删除重复值

Question

我有一个类ClientState

Class ClientState 
{ 
Public int ID{get;set;} 
public string State{get;set;} 
} 

List<ClientState> listClientState包含，可能现在美国各州的问题是listClientState包含一些对象具有重复的状态。 如何过滤listClientState删除重复记录

Answer 1

你尝试listClientState.Distinct().ToList()

Answer 2

你可以写一个比较器

class ClientStatesComparer : IEqualityComparer<ClientState> 
{ 
    public bool Equals(ClientState x, ClientState y) 
    { 
     return x.State = y.State; 
    } 

    public int GetHashCode(ClientState obj) 
    { 
     return obj.State; 
    } 
} 

，并使用

listClientState = listClientState.Distinct(new ClientStatesComparer()).ToList(); 

你当然会松动记录（即松开身份证）这种方式。如果每个ID都是一个国家的唯一身份，Veers解决方案就可以做到。

Answer 3

你可以使用HashSet<>，它不允许重复（它只是在Add（）上忽略它们）。除了公布答案，你也可以创建一个列表HashSet的，和所有的副本都将被忽略：

HashSet<ClientState> noDupes = new HashSet<ClientState>(listWithDupes); 
List<ClientState> listNoDupes = noDupes.ToList(); 

Answer 4

很简单的例子：

public class ClientState : IComparable<ClientState> 
{ 
    public int ID { get; set; } 
    public string State { get; set; } 

    public override string ToString() 
    { 
     return String.Format("ID: {0}, State: {1}", ID, State); 
    } 

    #region IComparable<ClientState> Members 

    public int CompareTo(ClientState other) 
    { 
     return other.State.CompareTo(State); 
    } 

    #endregion 
} 

static void Main(string[] args) 
     { 

      List<ClientState> clientStates = new List<ClientState> 
               { 
                new ClientState() {ID = 1, State = "state 1"}, 
                new ClientState() {ID = 2, State = "state 1"}, 
                new ClientState() {ID = 4, State = "state 3"}, 
                new ClientState() {ID = 11, State = "state 2"}, 
                new ClientState() {ID = 14, State = "state 1"}, 
                new ClientState() {ID = 15, State = "state 2"}, 
                new ClientState() {ID = 21, State = "state 1"}, 
                new ClientState() {ID = 20, State = "state 2"}, 
                new ClientState() {ID = 51, State = "state 1"} 
               }; 

      removeDuplicates(clientStates); 
      Console.ReadLine(); 
     } 

     private static void removeDuplicates(IList<ClientState> clientStatesWithPossibleDuplicates) 
     { 
      for (int i = 0; i < clientStatesWithPossibleDuplicates.Count; ++i) 
      { 
       for (int j = 0; j < clientStatesWithPossibleDuplicates.Count; ++j) 
       { 
        if (i != j) 
        { 
         if (clientStatesWithPossibleDuplicates[i].CompareTo(clientStatesWithPossibleDuplicates[j]) == 0) 
         { 
          clientStatesWithPossibleDuplicates.RemoveAt(i); 
          i = 0; 
         } 
        } 
       } 
      } 
     } 

输出：

ID: 4, State: state 3 
ID: 20, State: state 2 
ID: 51, State: state 1