Can I use .NET 4 with SharePoint 2007?

Question

I'm on a team that's currently building a MOSS 2007 based application (which relies on .NET 2), and we'd like to leverage the Entity Framework v4 (which relies on .NET 4).

Is this possible?

Answer 1

No. The 4.0 version of .NET has a new CLR (4.0) etc., but SharePoint 2007 is only supported on CLR 2.0.

Even SP2010 does not support .net 4.0 (yet).

Answer 2

Although I haven't tried, my guess is that it's not possible. In order to use .net 4.0 assemblies, the apppool running your moss site would have to be upgraded to the 4.0 version of asp.net. After that, version of system.web and other assemblies will change and I think that moss will simply stop working. But hey, it's just my guess. You can always try it out.