How do I make Visual Studio 2010 RC solution files compatible with previous versions?

Question

I'm trying to use visual studio 2010. But it seems that the .sln file that is created through it isn't supported by previous versions. Is it possible to save the projects in a way that it could be readable by previous versions of visual studio (2008).

Answer 1

The accepted answer is incorrect when it comes to projects. It's correct for solution files, but they're not actually as important as the project files (as they don't change as often, in my experience, and there are fewer of them).

For example, you might want to look at Noda Time. We have two solution files (NodaTime VS2008.sln and NodaTime VS2010.sln) which load the same project files. This provides a pretty practical solution to having developers working with different versions of Visual Studio.

Manually change the first part of the project file to look like this:

<Project ToolsVersion="4.0" DefaultTargets="Build" 
         xmlns="http://schemas.microsoft.com/developer/msbuild/2003"&gt;

(Basically just change ToolsVersion to 4.0.)

You can also just let VS2010 convert the projects automatically and compare them afterwards if you want - see whether it's done anything else that you don't want.

At that point, when you build in VS2008 you'll get output such as this:

Project file contains ToolsVersion="4.0", which is not supported by this version of MSBuild. Treating the project as if it had ToolsVersion="3.5".

... but it will still work, in my experience. There may be some oddities if you use a lot of designers etc, but generally it seems to work pretty well.