使用 Autofac 将参数传递给构造函数

问题描述

我对 autofac 很陌生，所以我可能完全误用了它.

I'm very new to autofac so it's possible that I'm completely misusing it.

假设我有一个具有这种结构的类:

Let's say I have a class that has this structure:

public class HelperClass : IHelperClass
{
     public HelperClass(string a, string b)
     {
         this.A = a;
         this.B = b;
     }
}

并且我有两个使用该类的类，但是构造函数需要不同的默认值.第二个构造函数仅用于测试目的——我们总是希望在真实"应用程序中有一个 HelperClass.:

and I have two classes that use that class, but require different defaults for the constructor. The second constructor is JUST for testing purposes -- we will always want a HelperClass in the "real" app.:

public class DoesSomething: IDoesSomething
{
     public DoesSomething()
         : this(new HelperClass("do", "something"));
     {

     }

     internal DoesSomething(IHelperClass helper)
     {
          this.Helper = helper;
     }
}

public class DoesSomethingElse : IDoesSomethingElse
{
     public DoesSomethingElse()
         : this(new HelperClass("does", "somethingelse"));
     {

     }

     internal DoesSomethingElse(IHelperClass helper)
     {
          this.Helper = helper;
     }
}

这是我的 AutoFac 模块:

Here's my AutoFac module:

public class SomethingModule: Module
{
    protected override void Load(ContainerBuilder builder)
    {
         builder.RegisterType<DoesSomething>().As<IDoesSomething>();
         builder.RegisterType<DoesSomethingElse>().As<IDoesSomethingElse();
    }
}

我的问题:

1. 当我对DoesSomething 或DoesSomethignElse 调用resolve 时——它会解析内部构造函数而不是公共构造函数吗?我需要让 IHelperClass 保持未注册状态吗?
2. 如果是，我如何让它根据 IHelperClass 是在DoesSomething 还是DoesSomethingElse 中使用，向每个IHelperClass 实例传递不同的参数?

推荐答案

Autofac 不使用非公共构造函数.默认情况下，它只找到公共的，根本看不到其他的.除非您使用 .FindConstructorsWith(BindingFlags.NonPublic)，否则它只会看到公共构造函数.因此，您的场景应该按照您的预期工作.

Autofac does not use non-public constructors. By default, it only finds public ones and simply doesn't see the others. Unless you use .FindConstructorsWith(BindingFlags.NonPublic), it will see only public constructors. Therefore your scenario should work as you expect it to do.

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