C#:微软为什么不让 ReadOnlyCollection 继承自 ReadOnlyCollectionBase？

Question

简单的说，微软定义了一个ReadOnlyCollectionBase , 但没有将其用作 ReadOnlyCollection<T> 的基类当听起来很明显应该是这样的时候。

我是不是漏掉了什么？我的意思是，是否有充分的理由不将此类作为基类？

Answer 1

可能是因为它不是通用的并且实现了 ICollection而ReadOnlyCollection<T>是通用的并实现了 ICollection<T> .注意 ICollection<T>不执行 ICollection .在那topic :

ICollection<T> seems like ICollection, but it’s actually a very different abstraction. We found that ICollection was not very useful. At the same time, we did not have an abstraction that represented an read/write non-indexed collection. ICollection<T> is such abstraction and you could say that ICollection does not have an exact corresponding peer in the generic world; IEnumerable<T> is the closest.

来自同一篇文章:

ReadOnlyCollection<T> is a much better ReadOnlyCollectionBase. It’s in System.Collections.ObjectModel namespace.

实际上，ReadOnlyCollection<T>是ReadOnlyCollectionBase在泛型领域。

注意，类似地，IList<T>不执行 IList .

一般来说，前泛型类不能用作泛型类的有用抽象(IEnumerable 除外)。