Question

我有以下课程

public class MyObject
{
    public int Id1 {get;set;}
    public int Id2 {get;set;}
    public int Id3 {get;set;}

    public MyObject(int id1, int id2, int id3)
    {
      this.Id1 = id1;
      this.Id2 = id2;
      this.Id3 = id3;
    }
}

我想在Dictionary中创建一个对象列表。我最好这样做吗

Dictionary<MyObject, MyObject> dictionary = new Dictionary<MyObject,MyObject>();

MyObject object1 = new MyObject(1,2,3);
MyObject object2 = new MyObject(2,2,3);
MyObject object3 = new MyObject(2,2,3);

if(!dictionary.ContainsKey(object1))
  dictionary.Add(object1,object1);

if(!dictionary.ContainsKey(object2))
  dictionary.Add(object2,object2);

if(!dictionary.ContainsKey(object3))
  dictionary.Add(object3,object3);

或者我应该创建一个字典，其中键是一个字符串，并包含连接的字符串。例如

Dictionary<string, MyObject> dictionary2 = new Dictionary<string,MyObject>();

string key = object1.Id1 + "|" + object1.Id2 + "|" + object1.Id3;

if(!dictionary2.ContainsKey(key ))
  dictionary2.Add(key ,object1);

Answer 1

在Equals或

GetHashCode

MyObject

将自定义IEqualityComparer<MyObject>传递给字典构造函数

但将此对象存储为键和值是没有意义的。也许您想要使用HashSet<MyObject>。

Answer 2

看起来你想要的是一个Hashset，因为键和值是相同的，你不想要重复。

您需要这个类来告诉哪些对象是相同的。

class MyObjectEqualityComparer : IEqualityComparer<MyObject>
{
    MyObjectEqualityComparer()
    {
    }

    public static readonly MyObjectEqualityComparer Default = new MyObjectEqualityComparer();

    public bool Equals(MyObject x, MyObject y)
    {
        return x.Id1 == y.Id1 && x.Id2 == y.Id2 && x.Id3 == y.Id3;
    }

    public int GetHashCode(MyObject obj)
    {
        return obj.Id1.GetHashCode() ^ obj.Id2.GetHashCode() ^ obj.Id3.GetHashCode();
    }
}

然后制作一个哈希集

HashSet<MyObject> set = new HashSet<MyObject>(MyObjectEqualityComparer.Default);


MyObject object1 = new MyObject(1,2,3);
MyObject object2 = new MyObject(2,2,3);
MyObject object3 = new MyObject(2,2,3);


if(set.Add(object1))
{
   // item was added.
}
else
{
   // item already exist.
}

我应该将我的对象用作字典键值或连接字符串

2 个答案: