Indicates to compilers that a method call or attribute should be ignored unless a specified conditional compilation symbol is defined.
#define CONDITION1 #define CONDITION2 using System; using System.Diagnostics; class Test { static void Main() { Console.WriteLine("Calling Method1"); Method1(3); Console.WriteLine("Calling Method2"); Method2(); Console.WriteLine("Using the Debug class"); Debug.Listeners.Add(new ConsoleTraceListener()); Debug.WriteLine("DEBUG is defined"); } [Conditional("CONDITION1")] public static void Method1(int x) { Console.WriteLine("CONDITION1 is defined"); } [Conditional("CONDITION1"), Conditional("Condition2")] public static void Method2() { Console.WriteLine("CONDITION1 or Condition2 is defined"); } }