是一个泛型类的静态成员联系在一起的具体实例？ [英] Are static members of a generic class tied to the specific instance?

问题描述

这是更多的是文档比真正的问题。这似乎并没有得到解决的SO，但（除非我错过了），所以这里有云：

This is more of a documentation than a real question. This does not seem to have been addressed on SO yet (unless I missed it), so here goes:

想象一个包含静态成员泛型类：

Imagine a generic class that contains a static member:

class Foo<T> {
    public static int member;
}

是否有每个特定类的成员的一个新实例，或者是有仅用于所有的Foo型类的单个实例

Is there a new instance of the member for each specific class, or is there only a single instance for all Foo-type classes?

它可以很容易地通过code证实是这样的：

It can easily be verified by code like this:

Foo<int>.member = 1;
Foo<string>.member = 2;
Console.WriteLine (Foo<int>.member);

结果是什么，哪里是这种行为记录？

What is the result, and where is this behavior documented?

推荐答案

A 静态字段是所有实例共享的的同类型的。 美孚＆LT; INT＆GT; 和美孚＆LT;字符串＆GT; 两种不同的类型。这可以通过code以下行来证明：

A static field is shared across all instances of the same type. Foo<int> and Foo<string> are two different types. This can be proven by the following line of code:

// this prints "False"
Console.WriteLine(typeof(Foo<int>) == typeof(Foo<string>));

至于在哪里，这是记录在案，下面是部分的 1.6.5字段的C＃语言规范中（对于C＃3）：

As for where this is documented, the following is found in section 1.6.5 Fields of the C# Language Specification (for C# 3):

一个静态字段只标识一个   存储位置。不管有多少   创建类的实例，   还有的只有永远一个副本   静态字段。

A static field identifies exactly one storage location. No matter how many instances of a class are created, there is only ever one copy of a static field.

如前所述; 美孚＆LT; INT＆GT; 和美孚＆LT;字符串＆GT; 不是同一类;它们是从同一个通用类构成两个不同的类。在上述文​​件中4.4节是怎么发生这种情况概述：

As stated before; Foo<int> and Foo<string> are not the same class; they are two different classes constructed from the same generic class. How this happens is outlined in section 4.4 of the above mentioned document:

一个泛型类型声明，其本身   表示未绑定的泛型类型   用作蓝图，以形成许多   不同的类型，通过施加方式   类型参数。

A generic type declaration, by itself, denotes an unbound generic type that is used as a "blueprint" to form many different types, by way of applying type arguments.

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