#504 – Using the #else Directive

You can conditionally compile code using the #if and #endif preprocessor directive.  You can also use an #else clause between the #if and the #endif.

In the code below, we’ve commented out the definition of DOGSBARK, so the code between the #else and #endif will be compiled.

//#define DOGSBARK

using System;
using DogLibrary;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main()
        {
            Dog d1 = new Dog("Kirby", 12);
#if DOGSBARK
            d1.Bark();
#else
            d1.WagTail();
#endif
        }
    }
}

Note that the code after the #if directive is greyed out, while the code after the #else is formatted normally.