Generic repository in ASP.NET Core without having a separate AddScoped line per table in Startup.cs?

Question

I have a generic repository in my project. Consider the following controller snippet

public class Lookup1Controller : Controller {     readonly MyDbContext _db;      public Lookup1Controller(MyDbContext dataContext)     {         _db = dataContext;     }      public async Task<IActionResult> Index()     {          IGenericRepository<Lookup1> _repository = new GenericRepository<Lookup1>(_db);         var lookup1s = await _repository.SelectAll();          return  View(lookup1s);     } 

I don't see the need to have my Database reference both in my Generic repository as well as each of my controllers.

I refactor it to:

public class Lookup1Controller : Controller {     private IGenericRepository<Lookup1> _repository;      public Lookup1Controller(IGenericRepository<Lookup1> repository)     {         _repository = repository;     }      public async Task<IActionResult> Index()     {         var lookup1s = await _repository.SelectAll();          return  View(lookup1s);     }  } 

which is much neater and ASP.NET 5 best practice from what I read. but I will get the following error if I access that controller route in my browser:

InvalidOperationException: Unable to resolve service for type 'MyProject.Data.IGenericRepository`1[MyProject.Models.Lookup1]' while attempting to activate 'MyProject.Controllers.Lookup1. 

because of I haven't injected the GenericRepository to use the interface.

I add to my Startup.cs an AddScoped line for each and every of my tables in the ConfigureServices method

services.AddScoped<IGenericRepository<Lookup1>,GenericRepository<Lookup1>> (); services.AddScoped<IGenericRepository<Lookup2>,GenericRepository<Lookup2>> (); services.AddScoped<IGenericRepository<Lookup3>,GenericRepository<Lookup3>> (); services.AddScoped<IGenericRepository<Lookup4>,GenericRepository<Lookup4>> (); etc 

so that my code runs without throwing an exception.

However my database has about 100 simple lookup tables. When I look at the above 100 lines of code it just doesn't look right.

It feels like copy and paste code. Each time I add a new table by adding a new model and controller with view my code will compile without giving me an error. But if I run the program and go to that view I could get the controller run error if I forgot to add the AddScoped line to my Startup.cs. Not really good for maintainability.

My question:

1. Is it really best practice to have a services.AddScoped for each and every lookup table in the ConfigureServices method of Startup.cs?

2. It is a generic repository so isn't there be a way to write those 100 copy and paste lines in one line?

3. If not then what is the best practice way to do this using my code?

Answer 1

Just use the non-generic registration overloads (the ones where you need to pass the 2 Type objects.) Then provide the open generic types of both your interface and the implementation:

services.AddScoped(typeof(IGenericRepository<>), typeof(GenericRepository<>)); 

In your controller, add a dependency for a repository of a specific type (a closed generic type):

public HomeController(IGenericRepository<Lookup1> repository) {     ... } 

Answer 2

If you would like to register all IGenericRepository<> implementations in Assembly:

services.AddAllGenericTypes(typeof(IGenericRepository<>), new[] {typeof(MyDbContext).GetTypeInfo().Assembly}); 

With extension from: https://gist.github.com/GetoXs/5caf0d8cfe6faa8a855c3ccef7c5a541