Visual Studio 2010 and .Net 4 Beta 2

Question

Can anyone tell me if components made on .net 3.5 can work in .net 4.0, there are a number of components in my software that will have to be developed using .net 3.5, but the whole application must be based on wpf 4, which is on the .net 4 framework.

Answer 1

.NET 4 will allow in-process side-by-side compatibility with earlier versions of .NET, if that will solve your problem.

http://msdn.microsoft.com/en-us/library/ee518876%28VS.100%29.aspx

Why do some components have to be developed with .NET 3.5?

Answer 2

Yes. You can use assemblies targetting the 2.0 CLR (.NET 3.5) within a CLR 4.0 application.