Autofac registration with multiple assembies and differing EntityConnections - entity-framework

Question

We have two Assemblies that contain their own Entity-Framework EDMX & repositoriy objects. These are registered using Autofac in an ASP.NET webapplication.
These Assemblies are very similar of architecture (but differing EDMX) we have found that the last EntityConnection being registered is the EntityConnection that is being used in both Assemblies. We need to limit the usage of an EntityConnection to only be used by Types of an assembly or namespace.
var assembly = typeof(Activity).Assembly;
builder.RegisterAssemblyTypes(assembly).AsImplementedInterfaces();
builder.Register(reg => new EntityConnection(ConnectionString));
var assembly = typeof(User).Assembly;
builder.RegisterAssemblyTypes(assembly).AsImplementedInterfaces();
builder.Register(reg => new EntityConnection(ConnectionString));
Is there a way to register the EntityConnection and limit the depth of EntityConnection? Limit each EntityConnection to the assembly it belong to?
Here's a pseudocode example of how we want to register EntityConnection for use in only an assembly or namespace.
builder.Register(reg => new EntityConnection(ConnectionString)).ForNamespace("x");

Answer 1

try to solve the problem at an higher level of abstraction. Since you have two separate domains (one containing the Activity entity, and one containing the User entity), it would be convenient to have this explicitly in your application design. For instance, define a factory of some kind per domain:
public interface IActivityDomainContextFactory
{
ObjectContext CreateNew();
}
public interface IPeopleDomainContextFactory
{
ObjectContext CreateNew();
}
You can now easily create an implementation for each interface, register them in the Autofac ContainerBuilder and let your services depend on one of those interfaces, instead of depending them on a EntityConnection.
In this case you of course still have a dependency on the Entity Framework itself (see here for how to abstract that away), but this makes your configuration much easier, less fragile, better performing, and your application code more maintainable.
I hope this helps.

Answer 2

You probably want to name/key your registrations. See TypedNamedAndKeyedServices - Autofac
I think this solves half your problem, how to register the types. The other half is in the resolution. Since your doing autoregistration via assembly scanning, this might take a little more trickery.

Answer 3

There are plenty of good suggestions out there on improving this, so just recording my solution as a general sketch of how you'd do this in Autofac.
The trick is to use named services for the connections, then customise parameter resolution for types in each assembly so that the EntityConnection parameters get a named instance:
builder.Register(reg => new EntityConnection(ConnectionString))
.Named<EntityConnection>("activities");
builder.RegisterAssemblyTypes(typeof(Activity).Assembly)
.AsImplementedInterfaces()
.WithParameter(
(pi, c) => pi.ParameterType == typeof(EntityConnection),
(pi, c) => c.ResolveNamed<EntityConnection>("activities"));
builder.Register(reg => new EntityConnection(ConnectionString))
.Named<EntityConnection>("users");
builder.RegisterAssemblyTypes(typeof(User).Assembly)
.AsImplementedInterfaces()
.WithParameter(
(pi, c) => pi.ParameterType == typeof(EntityConnection),
(pi, c) => c.ResolveNamed<EntityConnection>("users"));