Do I have to convert my project file to use MSBuild 4?

I have a C# .proj file 开发者_Python百科that using .Net Framework 3.5. Currently the solution that ties the .proj files uses Visual Studio 2008. Our daily build currently uses MSBuild 3.5. I know that you can specify the TargetFramework in MSBbuild 4.

My question is: do I have to convert my project file using Visual Studio 2010? I am assuming the conversion only affects the .sln file.

Conversion using Visual Studio 2010 is the easiest way, but you can just update your project files manually: just add ToolsVersion="4.0" attribute on the Project node. So yes, you have to convert your .proj files too, changing only the .sln is not enough.