向Autofac注册基类的实现以通过IEnumerable传递 [英] Registering implementations of base class with Autofac to pass in via IEnumerable

问题描述

我有一个基类，还有一系列其他继承自此的类:
(请原谅过度使用的动物类比)

公共抽象类动物{}

公共课狗:动物{}

公共课程Cat:动物{}

然后我有了一个依赖于IEnumerable<Animal>

的类

public class AnimalFeeder
{
    private readonly IEnumerable<Animal> _animals;

    public AnimalFeeder(IEnumerable<Animal> animals )
    {
        _animals = animals;
    }
}

如果我手动执行以下操作:

var animals =
    typeof(Animal).Assembly.GetTypes()
        .Where(x => x.IsSubclassOf(typeof(Animal)))
        .ToList();

然后我可以看到它返回了Dog和Cat

但是，当我尝试像这样连接Autofac时:

builder.RegisterAssemblyTypes(typeof(Animal).Assembly)
    .Where(t => t.IsSubclassOf(typeof(Animal)));

builder.RegisterType<AnimalFeeder>();

实例化AnimalFeeder时，没有任何Animal传递给构造函数.

我错过了什么吗?

解决方案

您在注册中缺少As<Animal>()呼叫.

没有它，Autofac将使用默认的AsSelf()设置注册您的类型，因此，仅当您使用诸如Dog和Cat之类的子类型时，如果您请求使用IEnumerable<Animal>的基本类型，就不会得到您的类.

因此将您的注册更改为:

builder.RegisterAssemblyTypes(typeof(Animal).Assembly)
     .Where(t => t.IsSubclassOf(typeof(Animal)))
     .As<Animal>();

I have a base class, and a series of other classes inheriting from this:
(Please excuse the over-used animal analogy)

public abstract class Animal { }

public class Dog : Animal { }

public class Cat : Animal { }

I then have a class that has a dependancy on an IEnumerable<Animal>

public class AnimalFeeder
{
    private readonly IEnumerable<Animal> _animals;

    public AnimalFeeder(IEnumerable<Animal> animals )
    {
        _animals = animals;
    }
}

If I manually do something like this:

var animals =
    typeof(Animal).Assembly.GetTypes()
        .Where(x => x.IsSubclassOf(typeof(Animal)))
        .ToList();

Then I can see that this returns Dog and Cat

However, when I try to wire up my Autofac like this:

builder.RegisterAssemblyTypes(typeof(Animal).Assembly)
    .Where(t => t.IsSubclassOf(typeof(Animal)));

builder.RegisterType<AnimalFeeder>();

When AnimalFeeder is instantiated, there are no Animal passed in to the constructor.

Have I missed something?

解决方案

You are missing the As<Animal>() call in your registration.

Without it Autofac will register your types with the default AsSelf() setting so you won't get your classes if you ask for base type with IEnumerable<Animal> only if you use the sub-types like Dog and Cat.

So change your registration to:

builder.RegisterAssemblyTypes(typeof(Animal).Assembly)
     .Where(t => t.IsSubclassOf(typeof(Animal)))
     .As<Animal>();

这篇关于向Autofac注册基类的实现以通过IEnumerable传递的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！