What’s the Difference Between a Value Provider and Model Binder?

ASP.NET MVC 3 introduced the ability to bind an incoming JSON request to an action method parameter, which is something I wrote about before . For example, suppose you have the following class defined (keeping it really simple here): public class ComicBook { public string Title { get; set; } public int IssueNumber { get; set; } } And you have an action method that accepts an instance of ComicBook: [HttpPost] public ActionResult Update(ComicBook comicBook) { // Do something with ComicBook and return an action result } You can easily post a comic book to that action method using JSON. Under the hood, ASP.NET MVC uses the DefaultModelBinder in combination with the JsonValueProviderFactory to bind that value. A question on an internal mailing list...(read more) ...