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I know that the entire context of this issue is a bit specific, but I'll try to do my best explaining it. I'm performing a quite big importation from one ecommerce platform to nopCommerce.

nopCommerce works with Autofac as dependency injection container. Importing one product to nopCommerce involves some queries over nopCommerce tables and finally an insertion to the products table. These steps are repeated a lot of times, and Entity Framework context gets bigger, as it has to track more and more entities and trying to detect changes and figure out how many objects has to persist.

What I want to do is, in every iteration of the loop, renew the context, so it only tracks the entities associated to the current iteration. Obviously I want to achieve this, trying to not modify (as much as possible) nopCommerce core. In the container configuration, it is explicitly set that the EF context instances are given per http request (something I want to avoid, as I need a new instance per iteration).

An easy way to do it would be:

foreach job in jobs

    Eject all instances in container

    service1 = Container.RequestInstance<SomeServiceINeed>

    service2 = Container.RequestInstance<SomeServiceINeed2>

    DoTheJob

The thing is, I don't know how to accomplish this with Autofac. I have been trying to create a new ContainerBuilder and update the existing one, but _context.GetHashCode will always return the same instance.

Any idea about the best way to do it?

EDIT:

As it was suggested in the comments, I've tried to get the instances inside a lifetime scope. Basically:

 using (var lifeTime = EngineContext.Current.ContainerManager.Container.BeginLifetimeScope())
 {
        service1 = lifeTime.Resolve<SomeServiceINeed>();

        service2= lifeTime.Resolve<SomeServiceINeed2>();

        ..............

   }

But I get this exception:

No scope with a Tag matching 'AutofacWebRequest' is visible from the scope in which the instance was requested. This generally indicates that a component registered as per-HTTP request is being requested by a SingleInstance() component (or a similar scenario.) Under the web integration always request dependencies from the DependencyResolver.Current or ILifetimeScopeProvider.RequestLifetime, never from the container itself.

The services I'm trying to resolve, obviously depends also on a lot of different repositories and other services that are already defined in the container wiring (app start). Some of them are configured as 'PerHttpRequest'.

Thanks a lot!

Jacob
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    Did you look at registering components with InstancePerLifetimeScope , then create a scope per iteration, which is achieved via container.BeginLifetimeScope() , not sure it works in your use case but worth a try – mrvux Jun 01 '14 at 21:16
  • Thanks catflier, I didn't have any luck :). I've made an edit on the post, an thanks for your answer! – Jacob Jun 02 '14 at 07:57
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    You might want to look at this: [http://stackoverflow.com/questions/3956505/in-autofac-how-do-i-change-the-instance-that-is-registered-after-build-has-been][1] [1]: http://stackoverflow.com/questions/3956505/in-autofac-how-do-i-change-the-instance-that-is-registered-after-build-has-been – wooncherk Jun 04 '14 at 04:53

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