为什么HashSet< T>不实现IReadOnlyCollection< T> [英] Why HashSet<T> does not implement IReadOnlyCollection<T>?

问题描述

我刚刚发现.NET Fx现在有3个有用的界面：

1. IReadOnlyCollection< T>


2. IReadOnlyList< T>


3. IReadOnlyDictionary< K，V>

我有点困惑为什么 HashSet< T> 不实施 IReadOnlyCollection< T> ？有什么原因，或者微软只是忘了设置了？

UPD

在两个小时后，我发现在BCL中有很多集合，它们具有 .Count 属性，但不实现 IReadOnlyCollection< T& / code>接口。

UPD2

此帖子 http://social.msdn.microsoft.com/论坛/ en / netfxbcl / thread / b4fb991a-3f5c-4923-93d4-7cd5c004f859 以及 Immo Landwerth的回答，他在其中说出以下内容

除了List<>和Dictionary<>之外的其他集合是否更新为
支持这些接口？

当然。事实上，我们所有的内置集合类型已经
实现了IReadOnlyList<>和IReadOnlyDictionary<> ;.这意味着，
可以直接将List，T []或Dictionary<>的一个实例传递给一个需要一个IReadOnly版本的
API。

解决方案

在4.5版的框架中， HashSet< T> 未实施 IReadOnlyCollection< out T& c $ c>。

这个遗漏在框架的4.6版本中解决了（在上面的问题提出后大约12个月后）。

这些更正是不限于 HashSet< T> ，其他集合如 Stack< T> 和 队列< T> 已获得这些改进。

<对于任何遗漏的原因的猜测是未决的。它可能是监督或时间压力，但坦率地说，它没有什么影响。我怀疑，即使我们喜欢相关的轶事，即使从微软开发团队的直接投入也会有些主观。

I've just found that .NET Fx now has 3 useful interfaces:

1. IReadOnlyCollection<T>
2. IReadOnlyList<T>
3. IReadOnlyDictionary<K,V>

And I'm bit confused why HashSet<T> do not implement IReadOnlyCollection<T>? Are there any reasons, or Microsoft just forgot about sets again?

UPD

After two-hours googling I've found that there are many collections in BCL which has .Count property but do not implement IReadOnlyCollection<T> interface.

UPD2

I've found this post http://social.msdn.microsoft.com/Forums/en/netfxbcl/thread/b4fb991a-3f5c-4923-93d4-7cd5c004f859 and the answer by Immo Landwerth where he've said following

Will other collections besides List<> and Dictionary<> be updated to support these interfaces?

Absolutely. In fact, all of our built-in collection types already implement IReadOnlyList<> and IReadOnlyDictionary<>. This means, you can directly pass an instance of List, T[] or Dictionary<> to an API that takes an IReadOnly-version of it.

解决方案

In version 4.5 of the framework, HashSet<T> does not implement IReadOnlyCollection<out T>.

This omission was resolved in version 4.6 of the framework (released almost 12 months after the above question was asked).

These corrections are not limited to HashSet<T>, other collections such as Stack<T> and Queue<T> have received these improvements.

Speculation on the reason for any omission is moot. It may be oversight or time pressure but frankly, it is of little consequence. I suspect that even direct input from the Microsoft Development Team would be somewhat subjective, even if we enjoy associated anecdotes.

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