Unfortunately, because Visual Studio 2010 Beta 2 and ASP.NET MVC 2 Beta share components which are currently not in sync, running ASP.NET MVC 2 Beta on VS10 Beta 2 is not supported. Regarding Visual Studio 2010 and .NET 4 support, that is unfortunately not a feasible option. The most recent public release of VS2010 and .NET 4 is Beta 2. However, our internal builds of MVC 2 for VS2010 and .NET 4 depend on features that were available only after Beta 2. In other words, if we released what we have right now for VS2010 and .NET 4 then it wouldn’t even run.

The good news is that the Visual Studio 2010 Release Candidate will include a newer version of ASP.NET MVC 2. 

Highlights

As you might expect from a release candidate, most of the work focused on bug fixes and improvements to existing features. We also spent a lot of time on performance profiling and optimization.

Much of the focus on this release was in the client validation scripts. For example, the validation script was moved into its own file and can be included at the top or bottom of the page. Client validation also now supports globalization.

The other change related to validation is that the ValidationSummary now supports overloads where only model-level errors are displayed. This is useful if you are displaying validation messages inline next to each form field. Previously, these messages would be duplicated in the validation summary. With these new changes, you can have the summary display an overall validation message (ex. “There were errors in your form submission”) as well as a list of validation messages which don’t apply to a specific field.

What’s Next?

RTM of course! The RTM release of ASP.NET MVC will be included in the RTM release of Visual Studio 2010, which is slated for some time in March. The VS2008 version of ASP.NET MVC 2 might release earlier than that. We’re still working out those details.