title: Two C# project files for VS2010 and VS2012 in the same directory
body: <p>I'm writing a C# project which I want to compile both under VS2010 and VS2012. I want to have two different <code>.csproj</code> files for that, even though VS2010-project can be directly included in VS2012-solution. I want two different project files because of different target .NET-versions.</p>
  
  <p>Additionally, I want both projects to be named the same within different solutions for VS2010 and VS2012. The both should share the same <code>.cs</code>-files and, possibly, some resources.</p>
  
  <p>Easy task? Strange thing, but I don't know, how to do that properly.</p>
  
  <ul>
  <li><p>First approach, doesn't work: name project files as <code>MyProject10.csproj</code> and <code>MyProject12.csproj</code>, leave both in the <code>MyProject</code> folder. But in this case they are displayed in solution as <code>MyProject10</code> and <code>MyProject12</code>, not simply <code>MyProject</code>. If I rename one to <code>MyProject</code> in solution explorer, it automatically renames the corresponding project file.</p></li>
  <li><p>Second approach, works, but has drawbacks. Move project files into different subdirectories, named <code>VS10</code> and <code>VS12</code>, manually change include paths in <code>.csproj</code>-files, adding <code>..\</code> as a prefix. In this case I see strange shortcut-like arrows under the icons in solution explorer.</p></li>
  </ul>
  
  <p>The only bad thing for the second approach is that when I add new files in the project using solution explorer, this file is placed in the <code>VS10</code> subdirectory, not in the root project directory. But it seems like project directories for <code>.csproj</code>-files are the directories containing the file by design, and I use the dark side of the force which I really don't want to do.</p>
  
  <p>Any better ideas?</p>