It is not possible to inject IEnumerable<CommandOption> using Microsoft.Extensions.DependencyInjection

[mthamil]

I am trying out the new dependency injection support for models. For additionalServices, I am passing an IServiceProvider created using ServiceCollection.BuildServiceProvider() in Microsoft.Extensions.DependencyInjection.

It seems that this service provider always returns an empty enumerable even if there are no implementations of a given service. I suppose this is by design due to the ability to retrieve all implementations of a given service. Since additional services are consulted before getting to the case where IEnumerable<CommandOption> is injected using GetOptions() in the custom CommandLineUtils service provider, these options can't be injected.

[natemcmaster]

If I understand right, you're trying to inject a constructor like this?

class MyCommand(IEnumerable<CommandOptions> options)

If so, yeah, I see the problem. It's here

CommandLineUtils/src/CommandLineUtils/CommandLineApplication.cs

Lines 925 to 942 in 59f11a6

	if (_parent.AdditionalServices != null)
	{
	var retVal = _parent.AdditionalServices.GetService(serviceType);
	if (retVal != null)
	{
	return retVal;
	}
	}
	if (serviceType == typeof(IConsole))
	{
	return _parent._context.Console;
	}
	if (serviceType == typeof(IEnumerable<CommandOption>))
	{
	return _parent.GetOptions();
	}

. The addition services are consulted first. Given the IEnumerable behavior is not possible to disable in Microsoft.Extensions.DependencyInjection, I don't think it should be a problem to put IEnumerable<CommandOptions> first, before resolving additional services.

[mthamil]

Yes, that is exactly it. I didn't try it, but I assume it would happen with IEnumerable<CommandArgument> as well.

[natemcmaster]

This is an easy fix. I'm hoping to release 2.2.1 later this week, and this will be part of it.

[natemcmaster]

Fixed in 2.2.1 which is now on nuget.org

[mthamil]

Great, thanks!