Service Registration via Reflection in .NET

AppServiceRegistrant.cs

using Microsoft.Extensions.DependencyInjection;

namespace App.Services;
public class AppServiceRegistrant : ServiceRegistrant
{
    public AppServiceRegistrant(IServiceCollection services)
        : base(services) { }
        
    public override void Register()
    {
        services.AddScoped<ServiceA>();
        services.AddScoped<ServiceB>();
        //
        services.AddScoped<ServiceZ>();
    }
}

Program.cs

using App.Services;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddAppServices();

var app = builder.Build();
app.Run();

ServiceRegistrant.cs

using Microsoft.Extensions.DependencyInjection;

namespace App.Services;
public abstract class ServiceRegistrant
{
    protected readonly IServiceCollection services;
    
    public ServiceRegistrant(IServiceCollection services)
    {
        this.services = services;
    }
    
    public abstract void Register();
}

ServiceRegistration.cs

using System.Reflection;
using Microsoft.Extensions.DependencyInjection;

namespace App.Services;
public static class ServiceRegistration
{
    public static void AddAppServices(this IServiceCollection services)
    {
        IEnumerable<Type> registrants = Assembly
            .GetAssembly(typeof(ServiceRegistrant))
            .GetTypes()
            .Where(x =>
                x.IsClass
                && !x.IsAbstract
                && x.IsSubclassOf(typeof(ServiceRegistrant))
            );
            
        foreach (Type registrant in registrants)
            ((ServiceRegistrant)Activator.CreateInstance(registrant, services)).Register();
    }
}