C# DI with generic interface and parameters

Question

Given a generic interface and its implementation:

public interface IGenericInterface { ... }

public class GenericImplementation : IGenericInterface { ... }

I am registering this for DI using services.AddTransient(typeof(IGenericInterface<>), typeof(GenericImplementation<>));

This works fine, of course. But I would like to inject a setting/config from the appsettings.json, which is where I'm coming unstuck.

Usually, I'd register my dependencies with parameters using services.AddTransient(x => new Implementation(x.GetRequiredService(), configuration["SomeSetting"]);

Is it possible to pass parameters to a dependency when registering it by type?

user_19214431 · Answer

You should make use of the Options Pattern.

You need to bind the config to a class and register the class for DI. Then in the constructor for the class that needs the config, you pass it in via the constructor.

Documentation Here:

https://docs.microsoft.com/en-us/aspnet/core/fundamentals/configuration/options?view=aspnetcore-6.0

user_108796 · Answer

You should be injecting your configuration class into your other dependencies' classes, and let them pick out what they want. What you're doing is breaking that separation of concerns.

C# DI with generic interface and parameters

2 Answers