Creating the bootstrapper

The bootstrapper is responsible for initializing Autofac. It will be called at the startup of the application and run once. Let's create the bootstrapper, as shown in the following steps:

1. In the root of the News project, create a new file called Bootstrapper.cs.
2. Enter the following code:

using Autofac;
using News.ViewModels;

namespace News
{
    public static class Bootstrapper
    {
        public static void Initialize()
        {
            var containerBuilder = new ContainerBuilder();
            containerBuilder.RegisterAssemblyTypes(typeof(App).Assembly)
                            .Where(x =>   x.IsSubclassOf(typeof(ViewModel)));
    
            var container = containerBuilder.Build();
            Resolver.Initialize(container);
        }
    }
}

Autofac uses the ContainerBuilder class to configure and finally build the container that we will pass to our resolver. Think of a builder as something that collects a lot of information on what needs...