为什么HashSet的&LT; T&GT;没有实现IReadOnlyCollection&LT; T&GT;? [英] Why HashSet<T> does not implement IReadOnlyCollection<T>?
问题描述
我刚刚发现,.NET Fx的,现在有3个有用的界面:
- <一个href="http://msdn.microsoft.com/en-us/library/hh881542"><$c$c>IReadOnlyCollection<T>$c$c>
-
IReadOnlyList&LT; T&GT;
- <一个href="http://msdn.microsoft.com/en-us/library/hh136548"><$c$c>IReadOnlyDictionary<K,V>$c$c>
和我有点困惑,为什么<一href="http://msdn.microsoft.com/en-us/library/bb359438%28v=vs.110%29"><$c$c>HashSet<T>$c$c>不执行 IReadOnlyCollection&LT; T&GT;
?是否有任何理由,或微软刚刚忘了套了吗?
UPD
在两小时google搜索,我发现有很多藏品BCL拥有 .Count之间
财产,但不执行 IReadOnlyCollection&LT; T&GT ;。
接口
UPD2
我发现这个职位<一个href="http://social.msdn.microsoft.com/Forums/en/netfxbcl/thread/b4fb991a-3f5c-4923-93d4-7cd5c004f859">http://social.msdn.microsoft.com/Forums/en/netfxbcl/thread/b4fb991a-3f5c-4923-93d4-7cd5c004f859和答案的 IMMO Landwerth 的he've所说的下面,其中
请问除了名单,其中其他收藏;>词典&LT;>更新为 支持这些接口?
当然可以。事实上,我们的所有内置集合类型的已 实施IReadOnlyList&LT;>和IReadOnlyDictionary&LT;>。这意味着,就 可以直接通过列表中,T []或字典℃的实例;>到 API,它需要一个IReadOnly版本吧。
在4.5版本的框架,的 的HashSet&LT; T&GT;
不执行 IReadOnlyCollection&LT;出T&GT;
。
这遗漏是在框架4.6版本解决了(上面的问题近12个月后释放的要求)。
这些更正不限于的HashSet&LT; T&GT;
,其他收藏品如的 堆栈&LT; T&GT;
和的 问答LT; T&GT;
收到这些改进
揣测任何遗漏的原因是没有实际意义。这可能是疏忽或时间pressure但坦率地说,这是无关紧要的。我怀疑从微软开发团队甚至直接输入就有些主观,即使我们享受相关的轶事。
I've just found that .NET Fx now has 3 useful interfaces:
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.
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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