Register classes with primitive dependencies in ASP NET Core - asp.net-mvc

Question

I got baffled on how can i resolve connection string dependency on UserRepo once it is injected on an mvc controller by ASP NET Core's DI? Note that my repo is targeting NET 4.6. and uses either sql db with dapper orm. Tips and advice will do.
Heres the code.
Interface to be depended
public interface IUserRepo
{
List<User> GetAll();
}
Concrete class that will be injected to mvc controller and has its own dependency
public class UserRepo: IUserRepo
{
private string connectionString = "";
//Depends on a connectionstring
public UserRepo(string connectionString)
{
this.connectionString = connectionString;
}
public List<User> GetAll()
{
//create an sqlconnection using provided connectionstring
//return list from db...
}
}
on ASP MVC CORE's startup.cs
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc();
//inject UserRepo , how to resolve UserRepo's dependency?
services.AddScoped<IUserRepo, UserRepo>();
}

Answer 1

You should use the AddScoped overload that accepts a delegate:
services.AddScoped<IAccountRepo>(c => new AccountRepo("constr"));

Answer 2

I suggest you using configuration based on ASP.NET Core documentation
If you have configuration setting (appsettings.json) like this:
{
"ConnectionStrings": {
"DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=aspnet-WebApplication1-26e8893e-d7c0-4fc6-8aab-29b59971d622;Trusted_Connection=True;MultipleActiveResultSets=true"
},
}
And your Startup.cs:
private readonly IConfigurationRoot _configuration;
public Startup(IHostingEnvironment env)
{
_configuration = new ConfigurationBuilder()
.SetBasePath(env.ContentRootPath)
.AddJsonFile($"appsettings.json", optional:false, reloadOnChange:true)
.Build();
}
public void ConfigureServices(IServiceCollection services)
{
...
services.AddSingleton<IConfiguration>(provider => _configuration);
...
}
Then you can resolve it on the UserRepo easily:
public class UserRepo: IUserRepo
{
private readonly string connectionString;
public UserRepo(IConfiguration configuration)
{
this.connectionString = configuration.GetConnectionString("DefaultConnection");;
}
public List<User> GetAll()
{
//create an sqlconnection using provided connectionstring
//return list from db...
}
}