#if (C# Reference)

ref:http://msdn.microsoft.com/en-us/library/4y6tbswk.aspx 

 

 1 // preprocessor_if.cs
 2 #define DEBUG
 3 #define MYTEST
 4 using System;
 5 public class MyClass 
 6 {
 7     static void Main() 
 8     {
 9 #if (DEBUG && !MYTEST)
10         Console.WriteLine("DEBUG is defined");
11 #elif (!DEBUG && MYTEST)
12         Console.WriteLine("MYTEST is defined");
13 #elif (DEBUG && MYTEST)
14         Console.WriteLine("DEBUG and MYTEST are defined");
15 #else
16         Console.WriteLine("DEBUG and MYTEST are not defined");
17 #endif
18     }
19 }