How to resolve concrete classes in Unity Dependency Injection

Question

I seem to be stumped on how to implemented the strategy pattern with a DI container.

I have a strategy interface:

public interface IUserCompaniesInviteStrategy
    {
        bool InviteUserToCompany(UserCompaniesInviteRequest userCompaniesInviteRequest);
    }

and a couple of concrete classes:

public class ConcreteExistingUserInviteStrategy : IUserCompaniesInviteStrategy

public class ConcreteNewUserInviteStrategy : IUserCompaniesInviteStrategy

How do I wire up Unity with this?

    container.RegisterType<IUserCompaniesInviteStrategy, ConcreteExistingUserInviteStrategy>();
container.RegisterType<IUserCompaniesInviteStrategy, ConcreteNewUserInviteStrategy>();

obviously doesn't work...

I tried:

container.RegisterType<IUserCompaniesInviteStrategy<ConcreteExistingUserInviteStrategy>, ConcreteExistingUserInviteStrategy>();
        container.RegisterType<IUserCompaniesInviteStrategy<ConcreteNewUserInviteStrategy>, ConcreteNewUserInviteStrategy>();

with

public interface IUserCompaniesInviteStrategy<T>

That doesn't seem to work.

I think what I'd like to do here is use named types, so like:

container.RegisterType<IUserCompaniesInviteStrategy, ConcreteExistingUserInviteStrategy>("1");
            container.RegisterType<IUserCompaniesInviteStrategy, ConcreteNewUserInviteStrategy>("2");

However, I have constructor injection setup and using container.resolve isn't a good option for me because of n-tier architecture and chaining dependencies I'd have to resolve.

How can I inject a named type into a constructor? Is there a better way to do what I'm trying to do? (Create an interface that resolves to two concrete strategies)

Update:

I took a look at With Unity how do I inject a named dependency into a constructor? . The accepted answer won't work because I don't have a dependency on Unity in my domain, nor do I want it. I tried the StrategyResolver, but I'm getting:

  An error occurred when trying to create a controller of type 'UserController'. Make sure that the controller has a parameterless public constructor.

That is indicative of a DI problem.

The StrategyResolver and IStrategyResolver are the same as in the example:

public class StrategyResolver : IStrategyResolver
    {
        private IUnityContainer container;

        public StrategyResolver(IUnityContainer unityContainer)
        {
            this.container = unityContainer;
        }

        public T Resolve<T>(string namedStrategy)
        {
            return this.container.Resolve<T>(namedStrategy);
        }
    }

public interface IStrategyResolver
    {
        T Resolve<T>(string namedStrategy);
    }

My config:

container.RegisterType<IUserCompaniesInviteStrategy, ConcreteExistingUserInviteStrategy>("ExistingUser");
            container.RegisterType<IUserCompaniesInviteStrategy, ConcreteNewUserInviteStrategy>("NewUser");
            container.RegisterType<IStrategyResolver, StrategyResolver>();
            container.RegisterType<IUserFactory, UserFactory>();

Concretes:

public class ConcreteExistingUserInviteStrategy : IUserCompaniesInviteStrategy
public class ConcreteNewUserInviteStrategy : IUserCompaniesInviteStrategy

And then I call it like:

_strategyResolver.Resolve<IUserCompaniesInviteStrategy>("ExistingUser");

Not sure what's wrong with it.