Just recently after I had made some changes to configurations of my solution and project Visual Studio 2012 stopped recognizing my changes and therefore does not build my ch
I had the same problem and discovered the problem - I had unchecked my project's build checkbox in the solution's build configuration manager.
To check or fix this, right click on your solution, select "Configuration Manager", and then select the "build" checkbox for your project. This will make it so any changes to files in your project will force a rebuild when you run the application or just choose to build.