我该如何使用IEnumerator.Reset（）？

问题描述：

是如何完全正确的方法来调用IEnumerator.Reset$c$c>?

How exactly is the right way to call IEnumerator.Reset?

该文件说：

在重置方法提供了COM互操作性。它不一定需要被执行;相反，实施者可以简单地抛出一个 NotSupportedException异常。

The Reset method is provided for COM interoperability. It does not necessarily need to be implemented; instead, the implementer can simply throw a NotSupportedException.

好了，这是否意味着我不应该永远把它？

Okay, so does that mean I'm not supposed to ever call it?

这是的这样的诱人用于流量控制例外：

It's so tempting to use exceptions for flow control:

using (enumerator = GetSomeExpensiveEnumerator())
{
    while (enumerator.MoveNext()) { ... }

    try { enumerator.Reset(); } //Try an inexpensive method
    catch (NotSupportedException)
    { enumerator = GetSomeExpensiveEnumerator(); } //Fine, get another one

    while (enumerator.MoveNext()) { ... }
}

是，我们应该如何使用它呢？或者，我们不是为了从托管code使用它呢？

Is that how we're supposed to use it? Or are we not meant to use it from managed code at all?

答

从来没有的;最终这是一个错误。正确的方法来遍历序列比一次更多的是 .GetEnumerator（）再次呼吁 - 即使用的foreach 了。如果你的数据是不可重复的（或昂贵的重复），通过 .ToList（）或类似的缓冲吧。

never; ultimately this was a mistake. The correct way to iterate a sequence more than once is to call .GetEnumerator() again - i.e. use foreach again. If your data is non-repeatable (or expensive to repeat), buffer it via .ToList() or similar.

这是语言规范的迭代器块抛出异常此方法正式的需求的。因此，您的不能依赖于它的工作的。曾经。

It is a formal requirement in the language spec that iterator blocks throw exceptions for this method. As such, you cannot rely on it working. Ever.

我该如何使用IEnumerator.Reset（）？

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