什么是全球::关键字在C＃中使用？ [英] What is the usage of global:: keyword in C#?

问题描述

什么是全球:: 关键字在C＃中使用？我们什么时候必须使用这个关键字？

What is the usage of global:: keyword in C#? When must we use this keyword?

推荐答案

从技术上说，全球不是关键字：这是一个所谓的上下文关键字。这些有特殊意义只能在有限的程序上下文，可以用来作为背景之外标识符。

Technically, global is not a keyword: it's a so-called "contextual keyword". These have special meaning only in a limited program context and can be used as identifiers outside that context.

全球 CAN每当有歧义或当一个成员是隐藏的，应使用。从这里的href=\"http://msdn.microsoft.com/en-us/library/c3ay4x3d%28VS.80%29.aspx\">：

global can and should be used whenever there's ambiguity or whenever a member is hidden. From here:

class TestApp
{
    // Define a new class called 'System' to cause problems.
    public class System { }

    // Define a constant called 'Console' to cause more problems.
    const int Console = 7;
    const int number = 66;

    static void Main()
    {
        // Error  Accesses TestApp.Console
        Console.WriteLine(number);
        // Error either
        System.Console.WriteLine(number);
        // This, however, is fine
        global::System.Console.WriteLine(number);
    }
}

请注意，但是，全球当类型没有指定命名空间不起作用：

Note, however, that global doesn't work when no namespace is specified for the type:

// See: no namespace here
public static class System
{
    public static void Main()
    {
        // "System" doesn't have a namespace, so this
        // will refer to this class!
        global::System.Console.WriteLine("Hello, world!");
    }
}

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