C#预处理指令

下面的程序演示了条件指令的用法：

   #define DEBUG
   #define VC_V10
   using System;
   public class TestClass
   {
      public static void Main()
      {

         #if (DEBUG && !VC_V10)
            Console.WriteLine("DEBUG is defined");
         #elif (!DEBUG && VC_V10)
            Console.WriteLine("VC_V10 is defined");
         #elif (DEBUG && VC_V10)
            Console.WriteLine("DEBUG and VC_V10 are defined");
         #else
            Console.WriteLine("DEBUG and VC_V10 are not defined");
         #endif
         Console.ReadKey();
      }
   }

当上面的代码被编译和执行时，它会产生下列结果：

   DEBUG and VC_V10 are defined