Autofac with multiple implementations of the same interface

Question

I\'m using Autofac and would like to have multiple implementations of an interface. How can I configure Autofac so to resolve dependencies based on the current type?

Mor

Answer 1

4 options here: https://autofaccn.readthedocs.io/en/latest/faq/select-by-context.html

Option 1: Redesign Your Interfaces

ILoggingMessageHandler , IDoSomethingMessageHandler 

Option 2: Change the Registrations

builder.Register(ctx => new FinalHandler(ctx.Resolve()));
or
builder.Register(ctx => new FinalHandler(ctx.Resolve()));

Option 3: Use Keyed Services

builder.RegisterType()
           .WithParameter(
             new ResolvedParameter(
               (pi, ctx) => pi.ParameterType == typeof(IMessageHandler),
               (pi, ctx) => ctx.ResolveKeyed("something")));

Option 4: Use Metadata

public class FinalHandler
{
  public FinalHandler([WithMetadata("sendBy", "something")] IMessageHandler messageHandler) { ... }
}