使用Autofac注入特定类型 [英] Inject Specific Type With Autofac

问题描述

我想在满足某些条件时注入特定类型.例如，我有一个如下所示的界面.

I want to inject specific type when some conditions are met. For example, i have got an interface like below.

public interface IMyInterface{

}

还有两个实现此接口的类

And also two classes that implement this interface

public class MyClassA : IMyInterface {
}

和

public class MyClassB : IMyInterface {
}

最后，我有一些服务类将构造函数参数作为IMyInterface获得.

Finally i have some service class that gets a constructor parameter as IMyInterface.

public class ServiceA{
private IMyInterface _interfaceClass;
public ServiceA(IMyInterface interfaceClass){
_interfaceClass = interfaceClass
}
}

和

public class ServiceB{
private IMyInterface _interfaceClass;
public ServiceA(IMyInterface interfaceClass){
_interfaceClass = interfaceClass
}
}

现在由于某些体系结构限制， ServiceA必须将MyClassA作为构造函数参数，而 ServiceB必须将MyClassB作为构造函数参数.

Now because of some architectural constraints ServiceA must get MyClassA as constructor parameter and ServiceB must get MyClassB as constructor parameter.

通常我像下面那样使用Autofac

Normally i am using Autofac like below

var builder = new ContainerBuilder();
builder.RegisterType<MyClassA>().As<IMyInterface>().InstancePerApiRequest();

但是我找不到方法如何强制Autofac为特定类型选择正确的类型. 我查看了Named<>功能，但无法解决问题.

But i couldn't find the way how can i force Autofac to select right type for specific type. I looked to Named<> feature but couldn't solve problem.

推荐答案

听起来您违反了Liskov替代原则

It sounds like you have violated Liskov substitution principle

现在由于某些体系结构限制，ServiceA必须将MyClassA作为构造函数参数，而ServiceB必须将MyClassB作为构造函数参数.

Now because of some architectural constraints ServiceA must get MyClassA as constructor parameter and ServiceB must get MyClassB as constructor parameter.

我不确定Autofac是否支持基于上下文的注入-为什么不仅使每个Service依赖于其所需的实现?

I'm not sure that Autofac supports context based injection - why don't you just make each Service dependent on the implementation it requires?

public class ServiceA
{
    private IMyInterface _interfaceClass;
    public ServiceA(MyClassA interfaceClass)
    {
        _interfaceClass = interfaceClass
    }
}

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