Pfthb

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());