从封闭的泛型中提取泛型类型 [英] Extract Generic Type From Enclosing Generic

问题描述

我想要这样的东西:

class Foo<T>{...}

class Boo<T>{

   Queue<T> stuff = new Queue<T>();

   public void Boo(Foo<T>){...};
}

...

//Extract the generic type - string - to define the type
//of MyBoo.
var MyBoo = new Boo(new Foo<string>());

我收到错误消息通用类型'Boo'需要'1'类型参数.是的，我通过明确说明模板类型来解决此问题，但我想知道是否存在/可以提取该类型的方法隐式键入，而不必显式声明.

I get the error "generic type 'Boo' requires '1' type arguments. Ya, I fixed the problem by stating the template type explicitly, but I'd like to know if there was/is a way to extract that type implicitly, rather than having to state it explicitly.

该其他帖子可能相关，但我不确定.

推荐答案

您不能直接使用泛型类型的构造函数隐式地执行此操作，但是可以使用泛型方法，例如在非泛型类中:

You can't do it implicitly directly with the constructor of a generic type, but you could from a generic method, e.g. in a non-generic class:

public static class Boo
{
    public Boo<T> Create<T>(Foo<T> foo)
    {
        return new Boo<T>(foo);
    }
}

然后:

// myBoo will be inferred to be of type Boo<string>
var myBoo = Boo.Create(new Foo<string>());

当然，没有是另一个名为Boo的类-可能是完全不同的东西，并且可能是其他东西的实例方法:

Of course, it doesn't have to be another class called Boo - it could be something completely different, and it could be an instance method of something else:

var factory = new BooFactory();
var myBoo = factory.Create(new Foo<string>());

重要的一点是，它是通用的方法-类型参数可以针对通用方法进行推断，而不能针对通用类型进行推断.

The important point is that it's a generic method - type arguments can be inferred for generic methods, but not for generic types.

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