Moves IControllerArgumentBinder and IControllerPropertyActivator into
.Internal. Also renames ControllerArgumentBinder ->
DefaultControllerArgumentBinder for consistency with other controller
extensibility types.
We don't think these are 100% baked for our long term maintenance of the
product, and want to reserve the ability to make changes in the future.
We want this change to avoid MVC eagerly reading the form. This is good
for general perf and also for scenarios where you want read the body
yourself (large file uploads).
We DO have scenarios where you want to configure the value providers
per-request or also to change the limits on the value providers (form) so
it's worth keeping these around on the context.
This commit introduces application parts as a concept on MVC.
An application part is an abstraction that allows you to expose some
feature or corncern in a way that is decoupled from their underlying source.
Examples of this include types in an assembly, emdeded resources, files on
disk etc.
Application parts are configured during startup by adding or removing them from
the application part manager available as part of IMvcBuilder and IMvcCoreBuilder.
The application part manager provides the ability to populate features from the
list of available application parts by using a list of application feature providers.
Application feature providers are responsible for populating a given feature given a
list of application parts.
Examples of application providers can be a ControllerFeatureProvider
that goes through the list of application parts, sees which one of those parts exposes types,
determines which of those types are controller types, and adds them to a ControllerFeature
that holds a list of all the types that will be considered controllers in the application.
This change separates model binding into IModelBinderProvider (decides
which binder to use) and IModelBinder (does binding). The
IModelBinderFactory is a new services with coordinates the creation of
model binders.