DependencyInjection.Extensions

Provides name-based registrations to Microsoft.Extensions.DependencyInjection

Nuget link

See origin https://stackoverflow.com/a/39276306/2528649

Usage example

In order to register your services you'll need to add following code to your Startup class:

    services.AddTransient<ServiceA>();
    services.AddTransient<ServiceB>();
    services.AddTransient<ServiceC>();
    services.AddByName<IService>()
        .Add<ServiceA>("key1")
        .Add<ServiceB>("key2")
        .Add<ServiceC>("key3")
        .Build();

Then you can resolve the appropriate service in two ways.

1. Injecting the dependency from factory registration.

    services.AddScoped<AccountController>(s => new AccountController(s.GetServiceByName<IService>("key2")));
   

In this case your client code is clean and has only dependency to IService and all the name resolution is performed on the factory expression.

2. Injecting dependency to IServiceByNameFactory interface:

    public AccountController(IServiceByNameFactory<IService> factory) {
        var name = "key2"; // here you can have custom code of name resolution
        _service = factory.GetByName(name);
    }
   

In this case your client code depends on both IServiceByNameFactory and IService which can be heplful in case when client has its own logic of name resolution.