LINQ和放大器;层次分明，实现equals和放大器; gethash code

问题描述

所以我努力使这项工作，我似乎无法知道为什么它不能正常工作

so I'm trying to make this work and I can't seem to know why it doesn't work

演示code;

namespace ConsoleApplication1
{
class Program
{
    static void Main(string[] args)
    {
        var myVar = new List<parent >();
        myVar.Add(new parent() { id = "id1", blah1 = "blah1", c1 = new child() { blah2 = "blah2", blah3 = "blah3" } });
        myVar.Add(new parent() { id = "id1", blah1 = "blah1", c1 = new child() { blah2 = "blah2", blah3 = "blah3" } });

        var test = myVar.Distinct();

        Console.ReadKey();

    }
}


public class parent : IEquatable<parent>
{
    public String id { get;set;}
    public String blah1 { get; set; }
    public child c1 { get; set; }

    public override int GetHashCode()
    {
        unchecked // Overflow is fine, just wrap
        {
            int hash = 17;
            // Suitable nullity checks etc, of course :)
            hash = hash * 23 + id.GetHashCode();
            hash = hash * 23 + blah1.GetHashCode();
            hash = hash * 23 + (c1 == null ? 0 : c1.GetHashCode());
            return hash;
        }
    }

    public bool Equals(parent other)
    {
        return object.Equals(id, other.id) &&
            object.Equals(blah1, other.blah1) &&
            object.Equals(c1, other.c1);
    }

}

public class child : IEquatable<child>
{
    public String blah2 { get; set; }
    public String blah3 { get; set; }

    public override int GetHashCode()
    {
        unchecked // Overflow is fine, just wrap
        {
            int hash = 17;
            // Suitable nullity checks etc, of course :)
            hash = hash * 23 + blah2.GetHashCode();
            hash = hash * 23 + blah3.GetHashCode();
            return hash;
        }
    }

    public bool Equals(child other)
    {
        return object.Equals(blah2, other.blah2) &&
            object.Equals(blah3, other.blah3);
    }

}
}

任何人都可以发现我的错误（S）？

anyone could spot my error(s) ?

推荐答案

您需要重写等于（对象）方法：

public override bool Equals(object obj) {
    return Equals(obj as parent);
}

在的Object.Equals 办法（不像 EqualityComparer＆LT; T＆GT; .DEFAULT ）不使用 IEquatable 接口。因此，当你写的Object.Equals（C1，other.c1），它不会打电话给你的 Child.Equals（儿童）方法。

The object.Equals method (unlike EqualityComparer<T>.Default) does not use the IEquatable interface. Therefore, when you write object.Equals(c1, other.c1), it doesn't call your Child.Equals(Child) method.

您没有绝对需要做的父为好，但您真的应该的。

You don't absolutely need to do that for parent as well, but you really should.

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