J.,

The old assemblies actually work in VS 2010 and under .NET Framework 4. The changes done to support VS 2010 were such as setting the proper registry entries in installation so that all assemblies appear properly in Add Referemce/component selection dialogs.

Under VS 2010, you can use the old assemblies when targeting .NET 2.0, 3.0 or 3.5 – in which case they will run under CLR 2.0; or you can even use the old assemblies when you are targeting 4.0 – in which case they will run under CLR 4.0.

However the new assemblies are specifically targeted to .NET Framework 4. They are not using any special features of it though (or yet). So the new assemblies are e.g. for customers who start a very fresh project with all modern stuff, so they get better “feeling” having assemblies targeted to .NET Framework 4 – but not really any functional difference I am aware of. I suspect that CLR 4.0 must do some extra things to load and run the older assemblies, but it appears to work well too.

The bottom line is that I would suggest that people who target .NET Framework 4 use the new assemblies, as they are simply better fit, but there is currently no hard reason for it.

Best regards,
<span style="font-family: "Arial","sans-serif"; color: #1f497d; font-size: 10pt">Zbynek Zahradnik

<span style="font-family: "Tahoma","sans-serif"; font-size: 10pt">From:<span style="font-family: "Tahoma","sans-serif"; font-size: 10pt"> J.
Sent: Monday, November 01, 2010 1:20 PM
......

Zbynek,

I noticed that you made a separate set of assemblies targeting .NET Framework 4.0. Did you have to do that to make them work with Visual Studio 2010? Or did you do this to take advantage of special things in .NET Framework 4.0?

J.