Unity - Inject different classes for the same interface

Question

I have one interface: IFoo
Two classes implementing that interface: FooOne and FooTwo
And two classes ClassOne and

Answer 1

You need to give them registration names to do this:

// Create an instance of a service you want to use. Alternatively, this
// may have been created by another process and passed to your application
LoggingService myLoggingService = new LoggingService();

// Register the existing object instance with the container
container.RegisterInstance("Logging", myLoggingService);

// Register a mapping for another service your application will use
container.RegisterType("DataService");

// When required, retrieve an instance of these services
IMyService theDataService = container.Resolve("DataService");
IMyService theLoggingService = container.Resolve("Logging");

Taken from Resolving Instances Of Types Using Unity