如何在C＃中为内置类型添加别名？ [英] How to alias a built-in type in C#?

问题描述

所以在C ++中，我习惯于做到：

So in C++, I'm used to being able to do:

typedef int PeerId;

这使我可以使类型更具自记录性，但同时也可以使PeerId表示随时更改为其他类型，而无需更改所有代码。如果需要，我甚至可以将PeerId转换为类。我想在C＃中拥有这种可扩展性，但是我在弄清楚如何在C＃中为'int'创建别名时遇到了麻烦。

This allows me to make a type more self-documenting, but additionally also allows me to make PeerId represent a different type at any time without changing all of the code. I could even turn PeerId into a class if I wanted. This kind of extensibility is what I want to have in C#, however I am having trouble figuring out how to create an alias for 'int' in C#.

我想我可以使用using语句，但是我相信它仅在当前文件中具有作用域，因此将不起作用（别名需要在多个文件之间进行访问而无需重新定义）。我也不能从内置类型派生一个类（但是通常这是我要为引用类型（例如List或Dictionary）加别名的方法。我不确定该怎么办。有想法吗？

I think I can use the using statement, but it only has scope in the current file I believe, so that won't work (The alias needs to be accessible between multiple files without being redefined). I also can't derive a class from built-in types (but normally this is what I would do to alias ref-types, such as List or Dictionary). I'm not sure what I can do. Any ideas?

推荐答案

您可以（ab）使用隐式转换：

You could (ab)use implicit conversions:

struct PeerId
{
    private int peer;

    public static implicit operator PeerId(int i)
    {
        return new PeerId {peer=i};
    }

    public static implicit operator int(PeerId p)
    {
        return p.peer;
    }
}

这与int占用相同的空间，而您可以做到：

This takes the same space as an int, and you can do:

PeerId p = 3;
int i = p;

但是我同意您可能不需要。

But I agree you probably don't need this.

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