Question

我有一个类ClientState

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

List<ClientState> listClientState包含USA的所有状态，现在问题可能是listClientState包含一些具有重复状态的对象。如何过滤listClientState以删除重复记录

Answer 1

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();

你当然会以这种方式放松记录（即松散身份证）。如果每个ID对于一个州都是唯一的，Veers解决方案就会这样做。

Answer 2

你试过listClientState.Distinct().ToList()

吗？

Answer 3

您可以使用HashSet<>，它不允许重复（它只是在Add（）上忽略它们）。除了发布的答案，您还可以从列表中创建一个HashSet，并忽略所有重复项：

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

Answer 4

非常简单的例子：

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;
                        }
                    }
                }
            }
        }

<强>输出：

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

删除重复值

4 个答案: