Resolving Generic Interface with Autofac

Question

Given the following code, how do I resolve the right SomeInstance in autofac?

public class BaseClass {}

public class SubClass1 : BaseClass {}

public class          


        

Answer 1

Autofac supports open generics. You can use the following code if generics type is known at compile time:

var builder = new ContainerBuilder();

builder.RegisterGeneric(typeof(SomeInstance1<>))
  .As(typeof(IGenericInterface<>));              

var container = builder.Build();

var instance1 = container.Resolve>();

Assert.IsInstanceOfType(typeof(SomeInstance1), instance1);

If type parameter is not known until runtime (which is likely your case if you want to iterate through collection of types) then you can build your type using MakeGenericType:

        var typeInRuntime = typeof (SubClass1);
        var instance1 = container.Resolve(typeof(IGenericInterface<>).MakeGenericType(typeInRuntime));