title: How can you link to a different version of MFC from a Visual C++ project in Visual Studio 2010?
body: <p>I have a VC++ project in VS2010 that is linking to some dll's built with VS2008.  Works fine until I try to pass MFC objects to the VS2008 dll.  The artifact of the VS2010 VC++ project (a .dll) is linking against the latest version of MFC that shipped with VS2010, whereas the VS2008 .dll is linking against the previous version of MFC that shipped with VS2008.</p>
  
  <p>VS2010 VC++ projects have a "Platform Toolset" property that allows either v90 (VS2008) or v100 (VS2010) and that seems like it ought to do the trick.  However, the VS2010 VC++ project is being built with /clr (Common Language Runtime Support), which seems to require targeting v4.0 of the .NET Framework - which is not supported in the v90 (VS2008) toolset.</p>