How to determine current Visual Studio configuration at runtime?

Three steps:
1.      Add a new configuration into solution
2.      In the property of this project, Add a Conditional Compilation Symbol for this configuration
3.      In code, check if this symbol existed by Preprocessor directives.

        public static bool ProVersion

        {

            get

            {

#if PRO_VERSION

                return true;

#else

                return false;

#endif

            }

        }

Reference:

http://stackpopstudios.com/tutorial-using-visual-studio-solution-configuration-to-manage-free-vs-paid/