什么是T [，]和T [*，*]之间的区别？ [英] What is the difference between T[,] and T[*,*]?

问题描述

我的谷歌柔术失败我。问题是在标题......是什么区别 T [，] 和 T [*，*] ？
我要寻找一个2，2-1 / 2的部分答案是：

My Google-Jitsu is failing me. Question is in the title... What is the difference between T[,] and T[*,*]? I am looking for a 2, 2-1/2 part answer:

1. 外行的（或超建筑师）纯英文的解释与例如code。

1. Layman's (or super architect's) plain english explaination with example code.

链接到这种区别的正式文件。

Link to the formal documentation of this distinction.

奖励：指向在定义这个C＃4款规格和页码。 （这不是在教派12阵列）

Bonus: Point to subsection and page number in the C# 4 spec that defines this. (It is not in sect 12 "Arrays")

我得到了这个概念<一href=\"http://social.msdn.microsoft.com/Forums/en/csharplanguage/thread/e6f84f77-1a09-4dd9-a2af-eb3a54e9c7bc\">here.

推荐答案

T [] 表示T的从零开始的数组的（数组[0]它的第一个元素）的

T[] means a zero-based array of T (array[0] is its first element)

T [*] 表示一个非从零开始的T阵列的（数组[0]是不是它的第一要素，甚至可以出界）的

T[*] means a non-zero-based array of T (array[0] is not its first element and can even be out of bounds)

的<一个href=\"http://social.msdn.microsoft.com/Forums/en/csharplanguage/thread/e6f84f77-1a09-4dd9-a2af-eb3a54e9c7bc\"相对=nofollow>从你的问题链接解释说，没有类型 T的数组[*，*] ，因为所有的多维数​​组 T [，] 被视为未知的约束下阵列。

The link from your question explains that there is no array of type T[*,*], because all multi-dimensional arrays of T[,] are treated as arrays with unknown lower-bound.

code片段展示了如何创建的一个实例T [*] 。请注意，你不能将它转换为 T [] ，因为它们是不同的类型。 A [0] 这里将抛出OutOfRangeException，第一个元素的数组索引为1的（啊，好老帕斯卡天......）

Code snippet below shows how you can create an instance of T[*]. Note that you can not cast it to T[], because they are different types. a[0] here will throw an OutOfRangeException, the index of the first element in this array is 1 (ah, good old Pascal days...).

Array a = Array.CreateInstance(typeof(String), new Int32[] { 1 }, new Int32[] { 1 });
Console.WriteLine(a.GetType());    // System.String[*]  

更多例如code

奖金 C＃语言规范说的阵列范围从0到长度元素的指数 - 1的。显然，语言不为非零基于阵列提供内置支持，它只是一个自定义的数据结构，您可以创建;虽然具体的编译器恰巧有其类型的特殊符号和VS使用标准的可视化阵列为他们当你正在调试的感觉。

Bonus. The C# language spec says, "The indices of the elements of an array range from 0 to Length - 1". Obviously, the language does not provide built-in support for non-zero-based arrays, it's just a custom data structure that you can create; although specific in a sense that the compiler happens to have a special symbol for its type and VS uses standard array visualizer for them when you're debugging.

另请参阅：

<一个href=\"http://stackoverflow.com/questions/5728409/how-to-create-a-1-dimensional-array-in-c-sharp-with-index-starting-at-1\">How建立在C＃中使用索引的一维数组中，以1

C＃：非零基于阵列是不符合CLS

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