Autofac。 使用参数向构造函数注册类

Question

I have the class custom class:

public class MyClass: IMyClass{
    public MyClass(String resolverNamespace){
       //Do some stuff dependent on resolverNamespace
    }
    //... Other stuff
}

public interface IMyClass{
   //... Other stuff
}

I need to register it in my autofac container to allow resolve instance depends on the namespace of caller. Thats how I expect it should be:

 //Registering in autofac
 builder.Register(x=>new MyClass(x.ResolveCallerNamespace)).As(IMyClass);

 // Somewhere in application
 namespace SomeNamespace{
 public SomeClass{
      public void SomeMethod(){
      {
         // Here i need to resolve MyClass instance(calling new MyClass("SomeNamespace"))
         var instance = container.Resolve<IMyClass>();
      }
 }
 }

Any Idea? Thx.

Answer 1

The only way you are going to be able to do that in the registration is by navigating up the stack trace to the original call site and then examine the namespace of the class where the Resolve call was made. If this object is constructed infrequently, then that is probably acceptable. However if the object is likely to be constructed very often then you need another approach.

Also you should be aware that this approach is fragile as you can't guarantee how the caller will resolve the instance.

I think the correct way to do this in Autofac is just to pass the namespace as a constructor parameter:

builder.RegisterType<MyClass>().As<IMyClass>();

public SomeClass
{
    public void SomeMethod()
    {
         var factory = container.Resolve<Func<string, IMyClass>>();
         var instance = factory(this.GetType().Namespace);
    }
}

You could go further and specify:

public class MyClass
{
   public MyClass(object namespaceProvider)
      : this (namespaceProvider.GetType().Namespace)
   { }
}

Then:

var factory = container.Resolve<Func<object, IMyClass>>();
var instance = factory(this);

Makes the intention more explicit.