为什么我们不能将索引器产生的值作为ref或out参数传递给方法? [英] why we can't pass produced value by indexer as ref or out parameter to an method?

问题描述

使用索引器有两个重要限制.首先，因为索引器会执行
未定义存储位置，索引器产生的值不能作为ref或
传递 方法的out参数.其次，索引器必须是其类的实例成员.它
无法声明为静态.

1.为什么我们不能将索引器产生的值作为ref或out参数传递给方法?

2.为什么索引器不能是静态的?

There are two important restrictions to using indexers. First,because an indexer does
not define a storage location, a value produced by an indexer cannot be passed as a ref or
out parameter to a method. Second, an indexer must be an instance member of its class; it
cannot be declared static.

1. why we can''t pass produced value by indexer as ref or out parameter to an method?

2. why indexers can not be static?

推荐答案

您的引号非常准确地回答了您的第一个问题:
1)因为索引器未定义存储位置"

它不会产生任何与存储相关的值，因此您无法在其上添加引用.如果没有引用可以指向的值，则它不能是引用，因此不能作为引用传递.索引器不是数字:它是处于执行阶段的过程.

2)因为它是该类特定实例的索引器-如果它是静态的，它将是所有实例的全局索引器，这将是愚蠢的-如果您有两个列表，则全局索引器应返回其中的哪一个价值从何而来?如果它们具有不同数量的元素怎么办?索引器必须与特定的可索引实例相关，否则它们将无法工作！

Your quote answers your first question pretty exactly:
1) "because an indexer does not define a storage location"

It doesn''t produce any storage related value so you can''t pint a reference at it. If it doesn''t have a value that a reference can point at, it can''t be a reference, so it can''t be passed as a reference. An Indexer is not a number: it is a process in a stage of execution.

2) Because it is an indexer into a specific instance of the class - if it was static, it would be a global indexer for all instances, and that would be silly - if you have two lists which of them should a global indexer return a value from? What if they have a different number of elements? Indexers have to be related to the specific indexable instance, or they can''t work!

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