c# - Is it possible to remove an existing registration from Autofac container builder?

Question

Something along those lines:

builder.RegisterType<MyType>().As<IType>();
builder.RegisterType<MyType2>().As<IType>();
builder.DeRegisterType<MyType>().As<IType>()

var container = builder.Build();
var types = container.Resolve<IEnumerable<IType>>();
Assert.IsTrue(types.Count == 1);
Assert.IsTrue(types[0].GetType == typeof(MyType2));

Scenario: I go through bunch of assemblies and as I go I register types but I want to make sure that I have only one implementation of a given type. I need to do this before I create the container. I could track that on my own but it would be nice if Autofac could help me a bit.

Answer 1

This cannot be done directly using the ContainerBuilder, unless you start over with a new one. Mind you, having first built a container you should be able to construct a new container filtering away unwanted types and reusing the registrations from the first container. Like this:

...
var container = builder.Build();

builder = new ContainerBuilder();
var components = container.ComponentRegistry.Registrations
                    .Where(cr => cr.Activator.LimitType != typeof(LifetimeScope))
                    .Where(cr => cr.Activator.LimitType != typeof(MyType));
foreach (var c in components)
{
    builder.RegisterComponent(c);
}

foreach (var source in container.ComponentRegistry.Sources)
{
    cb.RegisterSource(source);
}

container = builder.Build();

This is hardly very elegant but it works. Now, if you could elaborate on why you want to do this, perhaps there is a better way.