[Feature Request] Generic ObjectFactory and ActivatorUtilities.CreateFactory

[TechnoBerry]

Is your feature request related to a problem? Please describe.

Currently when I want to use ObjectFactory created by ActivatorUtilities.CreateFactory I have to use explicit cast to destination type for the result of ObjectFactory's invocation.

Describe the solution you'd like

I think that it would be better to add a method to ActivatorUtilities with following signature ObjectFactory<T> CreateFactory<T>(Type[] argumentTypes) that allows to avoid explicit casts.

API Proposal

namespace Microsoft.Extensions.DependencyInjection
{
    public static partial class ActivatorUtilities
    {
        public static ObjectFactory CreateFactory(Type instanceType, Type[] argumentTypes) { throw null; }
+        public static ObjectFactory<T> CreateFactory<T>(Type[] argumentTypes) { throw null; }
        public static object CreateInstance(IServiceProvider provider, Type instanceType, params object[] parameters) { throw null; }
        public static T CreateInstance<T>(IServiceProvider provider, params object[] parameters) { throw null; }
    }
}

[analogrelay]

As described in aspnet/Announcements#411, this code has moved to dotnet/runtime (https://github.com/dotnet/runtime/blob/master/src/libraries/Common/src/Extensions/ActivatorUtilities/ActivatorUtilities.cs). Transferring this issue there.

[Dotnet-GitSync-Bot]

I couldn't figure out the best area label to add to this issue. Please help me learn by adding exactly one area label.

[analogrelay]

cc @ericstj

[GrabYourPitchforks]

Related: #36194

[maryamariyan]

Seems like a straightforward API addition. Set it up as api-ready-for-review. This might also help with linkability.

[bartonjs]

Video

• Consider, in the future, adding more generic overloads that avoid the Type[] and object?[]? elements for pre-known signatures. These would probably use Func instead of new generic arities of ObjectFactory

namespace Microsoft.Extensions.DependencyInjection
{
    public delegate T ObjectFactory<T>(IServiceProvider serviceProvider, object?[]? arguments);

    public static partial class ActivatorUtilities
    {
        public static ObjectFactory<T> CreateFactory<T>(Type[] argumentTypes) { throw null; }
    }
}

[GrabYourPitchforks]

Related: #36194, though the scenario is a bit different, so there's room for both sets of APIs. I could easily see DI-specific functionality being written atop a generalized reflection factory API as value add.