Autofac configuration for ASP.Net Core 3.1 not working

Question

I am trying to use Autofac with ASP.Net Core 3.1 but I am getting an exception which does not make sense.

I am getting the following exception:

Autofac.Core.Activators.Reflection.NoConstructorsFoundException: 'No accessible constructors were found for the type 'Microsoft.AspNetCore.Mvc.ModelBinding.CompositeBindingSource'.'

I think the issue might be because of the order of services registered but I can't figure out what I am doing wrong. My configuration is as follows:

public class Program
    {
        public static void Main(string[] args)
        {
            CreateHostBuilder(args).Build().Run();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseServiceProviderFactory(new AutofacServiceProviderFactory())
                .ConfigureWebHostDefaults(webBuilder =>
                {
                    webBuilder.UseStartup();
                });
    }

Startup.cs class

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }
        public ILifetimeScope AutofacContainer { get; private set; }


        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllers();

            services.AddDbContext(options =>
                options.UseSqlServer(Configuration.GetConnectionString("DBConnection")));

            services.AddSwaggerGen();

            services.AddOptions();
        }

        public void ConfigureContainer(ContainerBuilder containerBuilder)
        {
            containerBuilder.RegisterModule(new AutofacModule());
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseHttpsRedirection();

            this.AutofacContainer = app.ApplicationServices.GetAutofacRoot();

            app.UseSwagger();

            app.UseSwaggerUI(c =>
            {
                c.SwaggerEndpoint("/swagger/v1/swagger.json", "eShop");
                c.RoutePrefix = string.Empty;
            });

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }

AutofacModule.cs class

public class AutofacModule : Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            // scan all assemblies in current application domain and resolve them on convention
            builder.RegisterAssemblyTypes(AppDomain.CurrentDomain.GetAssemblies())
                .AsImplementedInterfaces();
        }
    }

What am I missing?

user_1241992 · Answer

I was able to find the problem with the help of examples code...

The problem for me was in the AutofacModule.cs class. I was scanning the assembly incorrectly. Here is the working code.

public class AutofacModule : Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            // scan all assemblies in current application domain and resolve them on convention
            builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly())
                .AsImplementedInterfaces();
        }
    }

Autofac has examples of projects in Github and I found out that their documentation was different from their example code. This is the link of the ASP.Net Core 3.1 Example. for anyone who wants to see the configuration.

Autofac configuration for ASP.Net Core 3.1 not working

1 Answers