C# 修改 List.Contains 行为
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Modify List.Contains behavior
提问by Lancelot
I have a List<MyObj>with the class MyObj : IComparable. I wrote the method CompareToin the MyObjclass per the IComparableinterface, but when I use the List<MyObj>.Contains(myObjInstance)it returns falsewhen it should be true.
我有一个List<MyObj>用class MyObj : IComparable。我CompareTo在MyObj每个IComparable接口的类中编写了方法，但是当我使用List<MyObj>.Contains(myObjInstance)它false时它应该返回true。
I'm not sure I'm understanding how I need to proceed to make sure the Listuses my custom comparison method when calling then Containsfunction.
我不确定我是否理解我需要如何继续以确保List在调用 thenContains函数时使用我的自定义比较方法。
Here is my compareTo implementation:
这是我的 compareTo 实现：
#region IComparable Members
public int CompareTo(object obj)
{
MyObj myObj = (MyObj)obj;
return String.Compare(this.Symbol, myObj.Symbol, true);
}
#endregion
Note the Symbol property is a string.
注意 Symbol 属性是一个字符串。
To clarify I've put a stopping point in that compareTo method and it doesn't even go in there.
为了澄清，我在 compareTo 方法中设置了一个停止点，它甚至没有进入。
Anyone has ever tried that?
有人试过吗？
Thanks.
谢谢。
采纳答案by Fredrik M?rk
The absolute easiest way to find out whether your CompareTo method is called is to set a breakpoint in it and hit F5 to run your program. But I believe that List<T>.Containslooks for the IEquatable<T>interface for making the comparison.
确定是否调用了 CompareTo 方法的最简单方法是在其中设置断点并按 F5 运行程序。但我相信List<T>.Contains寻找IEquatable<T>用于进行比较的界面。
回答by Senthil Kumar
Did you try overriding the Equals method?
您是否尝试覆盖 Equals 方法？
List<T>, according to reflector, uses EqualityComparer<T>to check for containment, and the default implementation (ObjectEqualityComparer) uses Equals for most normal objects.
List<T>根据反射器的说法，用于EqualityComparer<T>检查包含情况，默认实现（ObjectEqualityComparer）对大多数普通对象使用 Equals。
回答by svick
According to the documentationfor List<T>.Contains, it uses either your implementation of IEquatableinterface or object.Equals, that you can override as well.
根据该文档的List<T>.Contains，它使用您的任何实施IEquatable的接口或object.Equals，你可以重写为好。
