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C# IEqualityComparer给出错误的结果_C#_Generics_Hashset - Fatal编程技术网

C# IEqualityComparer给出错误的结果

C# IEqualityComparer给出错误的结果,c#,generics,hashset,C#,Generics,Hashset,下面是我的测试代码,当它应该是时,它没有返回true: HashSet<TilePosition> test = new HashSet<TilePosition>(new TilePositionCompare()); test.Add(new TilePosition(10,10)); if (test.Contains(new TilePosition(10,10))) Debug.Log("We should see this"); 我不确定我会错在哪里。我已

下面是我的测试代码,当它应该是时,它没有返回true:

HashSet<TilePosition> test = new HashSet<TilePosition>(new TilePositionCompare());
test.Add(new TilePosition(10,10));

if (test.Contains(new TilePosition(10,10)))
Debug.Log("We should see this");
我不确定我会错在哪里。我已经学习了一些教程,它们似乎也在做同样的事情。

GetHashCode应该基于X/Y

public class TilePositionCompare : IEqualityComparer<TilePosition>
{
    public bool Equals(TilePosition tileA, TilePosition tileB)
    {
        return tileA.PosX == tileB.PosX && tileA.PosY == tileB.PosY;
    }

    public int GetHashCode(TilePosition tile)
    {
        var hash = 17;
        hash = hash * 23 + tile.PosX.GetHashCode();
        hash = hash * 23 + tile.PosY.GetHashCode();
        return hash;
    }
}

要知道为什么使用奇数素数17,请阅读此处:

GetHashCode应该基于X/Y

public class TilePositionCompare : IEqualityComparer<TilePosition>
{
    public bool Equals(TilePosition tileA, TilePosition tileB)
    {
        return tileA.PosX == tileB.PosX && tileA.PosY == tileB.PosY;
    }

    public int GetHashCode(TilePosition tile)
    {
        var hash = 17;
        hash = hash * 23 + tile.PosX.GetHashCode();
        hash = hash * 23 + tile.PosY.GetHashCode();
        return hash;
    }
}


要知道为什么使用奇数素数17,请阅读此处:

更一般地说,如果Equalsx,y对任意两个对象x和y都为真,那么GetHashCode的正确实现必须确保GetHashCodex==GetHashCodey。未能满足此要求是原始问题报告的错误结果的真正原因。更一般地说,如果Equalsx,y对于任意两个对象x和y为真,则GetHashCode的正确实现必须确保GetHashCodex==GetHashCodey。未能满足此要求是原始问题报告的错误结果的真正原因。您似乎在Equals方法中使用了属性PosX和PosY,它们在您的类中的何处?您似乎在Equals方法中使用了属性PosX和PosY,它们在您的类中的何处?
public class TilePositionCompare : IEqualityComparer<TilePosition>
{
    public bool Equals(TilePosition tileA, TilePosition tileB)
    {
        return tileA.PosX == tileB.PosX && tileA.PosY == tileB.PosY;
    }

    public int GetHashCode(TilePosition tile)
    {
        var hash = 17;
        hash = hash * 23 + tile.PosX.GetHashCode();
        hash = hash * 23 + tile.PosY.GetHashCode();
        return hash;
    }
}