.NET Core dependency injection -> Get all implementations of an interface

Question

I have an interface called IRule and multiple classes that implement this interface. I want to use the .NET Core dependency injection Container to load all implementations of IRule, so all implemented rules.

Unfortunately I can't make this work. I know I can inject an IEnumerable<IRule> into my ctor of the controller, but I don't know how to register this setup in the Startup.cs

Answer 1

It's just a matter of registering all IRule implementations one by one; the Microsoft.Extensions.DependencyInjection (MS.DI) library can resolve it as an IEnumerable<T>. For instance:

services.AddTransient<IRule, Rule1>();
services.AddTransient<IRule, Rule2>();
services.AddTransient<IRule, Rule3>();
services.AddTransient<IRule, Rule4>();

Consumer:

public sealed class Consumer
{
    private readonly IEnumerable<IRule> rules;

    public Consumer(IEnumerable<IRule> rules)
    {
        this.rules = rules;
    }
}

NOTE: The only collection type that MS.DI supports is IEnumerable<T>.