In section 7.4 of your book you discuss the creation of the C# WPF DLL and then the mixed-mode MFC extension C++ DLL. When I do the same, everything works great, builds fine, etc. initially.

But if I copy the code to another machine, I find I need to recreate the project reference between the C++ project and the C# project. Initially when I open the C++ project, the C# project reference is invalid. If I remove the C# project reference and recreate it, everything is fine from then on, even if I do a project clean and full rebuild.

Do you know why the project reference goes bad? Is there something I can do to avoid it? I've looked inside the project files and the reference is a relative path and valid. I'm not doing anything special in the project properties.

Thanks.

Normally, if you click on the reference name in Solution Explorer, Visual Studio should resolve the reference in about a second or two. But it does initially show it as a broken reference - even with SP1.