嵌套的通用接口 [英] Nested generic interfaces

问题描述

我有一个类似于以下(C#.NET4)的接口架构

I have a schema of interfaces like the following (C# .NET4)

interface A 
{

}

interface B 
{
    List<A> a;
}

interface C 
{
    List<B> b;
}

我以这种方式实现了

public interface A 
{

}

public interface B<T> where T : A 
{
    List<T> a { get; set; }
}

public interface C<T> where T : B
{
    List<T> b { get; set; } // << ERROR: Using the generic type 'B<T>' requires 1 type arguments
}

我不知道如何避免错误使用通用类型'B'需要1个类型参数

I don't know how to avoid the error Using the generic type 'B' requires 1 type arguments

推荐答案

由于interface B<T>是通用的，因此在声明interface C<T>时需要为其提供一个形式类型参数.换句话说，当前的问题是您没有告诉编译器继承"接口B的类型是什么.

Since interface B<T> is generic, you need to provide a formal type argument for it when declaring interface C<T>. In other words, the current problem is that you are not telling the compiler what type of interface B interface C "inherits" from.

两个T不一定引用相同的类型.它们可以是与

The two Ts will not necessarily refer to the same type. They can be the same type, as in

public interface C<T> where T : B<T>, A { ... }

或者它们可以是两种不同的类型:

or they can be two distinct types:

public interface C<T, U> where T : B<U> where U : A { ... }

在第一种情况下，对类型参数的限制当然会更严格.

The restrictions on the type argument are of course tighter in the first case.

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