Solution with vs2005 and vs2010 projects.Any problems

Question

I am currently working in a place where they still use .net 2.0. I would like to add some projects(. net 4.0) to existing solution .

Would this create any issues?

I suppose as long I use a "top down approach " I should be fine no?

Is there something that I am missing that could cause issues?

Answer 1

.NET 4.0 is isolated from previous versions, so you will have to add a setting to your app.config so 4 can see the other versions.

  <startup useLegacyV2RuntimeActivationPolicy="true">
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
  </startup>

I have one solution with five 2.0 projects and six 3.5 projects and one 4.0 project in Visual Studio 2010.

There were issues with the auto-generated designer code for Strongly-Typed DataSet classes that were fairly easy to resolve. I do suggest opening any entities that use designers so the auto-generated code is updated to Visual Studio 2010. This includes settings, resources, Windows.Form form/control classes, and so on.

Two other issues required updating to Crystal Reports for Visual Studio 2010 and updating to Visual Studio Tools for Office 3.0 for the projects that used Cystal Reports and Office.

Answer 2

There shouldn't be any problem, but i recommend to change your project to 4.0 then add the others.

Answer 3

Assuming you are using VS2010 as IDE No, this won't create any issue. Your .Net 2.0 projects will still be built against .Net framework 2 and similarly .Net 4 project will target .Net Framework 4.