为什么列表＆LT; T＆GT;实现IList＆LT;吨＆gt;中的ICollection＆LT; T＆GT;和IEnumerable＆LT; T＆GT ;? [英] Why does List<T> implement IList<T>, ICollection<T> and IEnumerable<T>?
问题描述
如果你去的定义列表＆LT; T＆GT; 你会看到以下内容：
If you go to definition of List<T> you would see the following:
public class List<T> : IList<T>, ICollection<T>, IEnumerable<T>
的IList＆LT; T＆GT; 从已经继承了的ICollection＆LT; T＆GT; 和的IEnumerable＆LT; T＆GT;
那岂不是有，如果已经足够名单＆LT; T＆GT; 只执行的IList＆LT; T＆GT;
Wouldn't it have been sufficient if List<T> only implemented IList<T>?
推荐答案
是的，这使得在这种情况下没有什么区别。在某些情况下，它的可以的有所作为，如果你使用的已实现接口的基类，但你要自己明确地重新实现它 - 但在这种情况下，没有基类（比其他隐对象），它会表现得完全相同的方式。
Yes, it makes no difference in this case. In some cases it can make a difference, if you're using a base class which already implements an interface but you wish to reimplement it yourself explicitly - but in this case there's no base class (other than the implicit object) and it would have behaved exactly the same way.
出乎我的回忆，我不相信有一个在类中重元psented $ P $的方式的差异$ C $是否Ç显式声明所有接口或没有。这里有一个例子：
Contrary to my recollections, I don't believe there's a difference in the way the class is represented in metadata whether the code explicitly declares all the interfaces or not. Here's an example:
interface IFoo {}
interface IBar : IFoo {}
class FooBar1 : IBar {}
class FooBar2 : IBar, IFoo {}
这两个ILDASM和反射显示 FooBar1 和 FooBar2 ...它显示了两者实现相同的信息伊巴尔和的IFoo 。
Both ildasm and Reflector show the same information for FooBar1 and FooBar2... it shows both of them implementing IBar and IFoo.
在换句话说，我们无法判断对原始出处code列表与LT; T＆GT; 其实指定所有接口或没有。也许是这样，也许它没有 - 但没关系不管怎样
In other words, we can't tell whether the original source code for List<T> actually specifies all the interfaces or not. Maybe it does, maybe it doesn't - but it doesn't matter either way.
编辑：为了完整起见，我还检查你在哪里扩展两个接口与另一个接口的情况下。我不能找到在这种情况下，元数据的差异，无论是。我敢肯定，我记得一些情况中，很明显，但现在我找不到它。
For completeness, I also checked the cases where you're extending two interfaces with another interface. I can't find a difference in the metadata in that case, either. I'm sure I remember some situation in which it was evident, but I can't find it now.
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