Cannot compile source file with Ctrl-F7 in VS 2008

Question

I have added an existing .cpp file to my project.  When I want to compile
only one file, I usually press Ctrl-F7, but that does not work on this file (it works on some other source files).  When I pull down the Build menu, the Compile option is missing, like it is when a header
(*.h) file is active.
When I right-click on the source file in the Solution Explorer, the context menu shows "Compile\tCtrl+F7"; I can compile a single source file that way, but Ctrl-F7 is so much easier and faster.
I have tried resetting the keyboard shortcut, resetting the profile to the original C/C++ profile, and closing and reopening Visual Studio, but nothing corrected the issue.
It feels like VS is not recognizing that my source file is a C++ file, despite its name (something.cpp).  Why has this started happening, and how can I get the shortcut (and Build menu) to reset?

Answer 1

This happens in the following way.  You manually create a new C++ class in an existing project using the editor in VC++.  You then (with the editor still open) add the file to your project.  Visual Studio finds your class info
and adds it intellisense, making it seem as though VC++ knows your file is in the project.  However, it does not and ctrl f7 will therefore not work.  Removing and adding the file does not help...unless you close the editor window...in which
case VC++ will correctly add the file if you remove and add it to your project.
This is not an uncommon way to create a new class - one does not always use the VC++ create class option.  The manual creation method may be preferable if you are not using automated features from VC++ and instead want to copy some code
from another file, headers for example.   My view is that this is a VC++ bug that should be repaired; apparently VC++ thinks the file is already included if it is open in the editor rather than checking its file list.  But it is easy
to work around once you know what is happening.