Xtykutl

I'm trying to implement 3-tier concept in my ASP.NET Core MVC application and I'm quite struggling with DI.

Here's a quick representation of solution structure :

• Business


• Common
  
  
  
  
  • User
  
  
  
  


• Data
  
  
  
  
  • AppDbContext
  
  
  
  


• Web
  
  
  
  
  • Controllers
  
  
  • Views
  
  
  
  

Business, Common, Data and Web are 4 different projects referencing each other when necessary.

Problem is, when I try to access the AppDbContext inside controllers, I get this error :

InvalidOperationException: Unable to resolve service for type 'com.jds.chat.Data.AppDbContext' while attempting to activate 'com.jds.chat..Web.Controllers.CustomCriMessengerClientBotController'

The AppDbContext.cs in the Data project:

public class AppDbContext : DbContext

{

    static string DbContextName = "AppDbConnectionString";



    public DbSet<User> Users { get; set; }



    public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)

    {

    }



    public AppDbContext(): base()

    {

    }



    protected override void OnModelCreating(ModelBuilder modelBuilder)

    {

    }



    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

    {

        if (!optionsBuilder.IsConfigured)

        {

            IConfigurationRoot configuration = new ConfigurationBuilder()

               .SetBasePath(Directory.GetCurrentDirectory())

               .AddJsonFile("appsettings.json")

               .Build();

            var connectionString = configuration

                                .GetConnectionString(DbContextName);

            optionsBuilder.UseSqlServer(connectionString, 

                            x => x.MigrationsAssembly("com.jds.chat..Data"));

        }

    }



    public virtual void Commit()

    {

        base.SaveChanges();

    }

}

The Container builder in the Data project:

public class AutoFacDataModule : Autofac.Module

{

        protected override void Load(ContainerBuilder builder)

        {        

            builder.RegisterType<AppDbContext>().InstancePerLifetimeScope();



        }

}

The controller in Web project :

private readonly AppDbContext _dbContext;



public ChatController(AppDbContext dbContext)

{

    _dbContext = dbContext;

}



public IActionResult Index()

{

    var users = _dbContext.Users.Where(u => u.IsInChat).ToList();

    return View();

}

The startup.cs in web project :

public class Startup

{

    public Startup(IConfiguration configuration)

    {

        Configuration = configuration;

    }



    public IConfiguration Configuration { get; }



    // This method gets called by the runtime. 

    // Use this method to add services to the container.

    public void ConfigureServices(IServiceCollection services)

    {

        services.Configure<CookiePolicyOptions>(options =>

        {

            // This lambda determines whether user consent 

            // for non-essential cookies is needed for a given request.

            options.CheckConsentNeeded = context => true;

            options.MinimumSameSitePolicy = SameSiteMode.None;

        });



        var builder = new ContainerBuilder();



        builder.RegisterModule(new AutofacBusinessModule());

        builder.RegisterModule(new Cri.Module.Chatbot.

                            Business.AutofacBusinessModule());

        services.AddMvc()

                .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);

    }



    // This method gets called by the runtime. 

    // Use this method to configure the HTTP request pipeline.

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)

    {

        if (env.IsDevelopment())

        {

            app.UseDeveloperExceptionPage();

            //app.UseDatabaseErrorPage();

        }

        else

        {

            app.UseExceptionHandler("/Home/Error");

            app.UseHsts();

        }



        app.UseHttpsRedirection();

        app.UseStaticFiles();

        app.UseCookiePolicy();



        app.UseMvc(routes =>

        {

            routes.MapRoute(

                name: "default",

                template: "{controller=Home}/{action=Index}/{id?}");

        });

    }

}

I'm missing something, but yet I don't see what...

You're registering the AppDbContext in the AutoFacDataModule, here:

public class AutoFacDataModule : Autofac.Module

{

    protected override void Load(ContainerBuilder builder)

    {        

        builder.RegisterType<AppDbContext>().InstancePerLifetimeScope();    

    }

}

But you're not registering that module with Autofac with anywhere in ConfigureServices. You're registering two other modules:

builder.RegisterModule(new AutofacBusinessModule());

builder.RegisterModule(new Cri.Module.Chatbot.Business.AutofacBusinessModule());

But not the AutodacDataModule. You need to add something like:

builder.RegisterModule(new AutofacDataModule());