Looks like the MVC team has put out preview release 5 of the MVC Framework today. You can get the latest version from CodePlex.
Here is what I can tell has changed from the release notes.
- Added global registration of view engines
- Changed the IViewEngine interface to add the RenderParial method
- Added support for rendering partial views
- Added a parameter to specify a default option label for DropDownList controls
- Moved ASP.NET AJAX extension methods to a separate namespace
- Added helpers for RadioButton and TextArea controls and made overall improvements to other helpers.
- Removed helper method overloads to avoid ambiguity
- Added array support for action method parameters
- Removed the ActionMethod property from action filter context objects
- Added support for custom model binders
- Added an IActionInvoker interface
- Added an UpdateMode method to the Controller class
- Changed HandleErrorAttribute so that it does not handle exceptions when HttpContext.IsCustomErrorEnabled is false
- Added a new AcceptVerbs attribute
- Added a new ActionName attribute
Known Issues and Breaking Changes
- Controller class now is derived from ControllerBase class
- Controller.Execute as removed, it is not called ExecuteCore.
- Controller initialization steps should be done in Initialize method now.
- IViewEngine interface is now responsible for finding views, not rendering them.
- Some overloads to some helper methods have been removed.
- AJAX helper methods have been moved to a new namespace.
- This version is incompatible with Visual Studio 2008 SP1 Beta
Upgrading from Preview 4 to Preview 5
- System.Web.Abstractions and System.Web.Routing have been changed to version 22.214.171.124
- Assemblies are located at %ProgramFiles%\Microsoft ASP.NET\ASP.NET MVC CodePlex Preview 5
Derik also noticed that many of the classes are still sealed, and is requesting that the team un-seals all classes, and I agree with him.
Breaking and mysterious changes that I have submitted a bug request for:
Update (2008-8-31): Also Derik found a replacement for RenderUserControl, very minor change, but it is the difference between a error and having the thing work.