如何覆盖字典的默认比较器？ [复制]

Question

如果我有字典

Dictionary<SomeClass, int> MyDict { get; set; } = ...

如何覆盖在评估键时调用的比较方法？

如 - 我想控制在我写作时选择哪个对象

MyDict[SomeClassInstance]

Answer 1

您需要实现IEqualityComparer<TKey> 并将其实例传递给字典的constructor：

public class MyComparer : IEqualityComparer<object>
{
    public bool Equals(object o1, object o2)
    {
        // implement your way of equality 
    }
    public int GetHashCode(object o)
    {
        // implement a hash method that returns equal hashes for equal
        // objects and well distributed hashes for not-equal objects
    }
}

Dictionary<object, int> myDict = new Dictionary<object, int>(new MyComparer());

Answer 2

您可能希望use the constructor 允许您传递IEqualityComparer<TKey> 的实例，然后将其用于您的键比较。我不相信你可以在实例化后改变它。