下表列出了所有C#支持的關係運算符。假設變量A=10和變量B=20，則：

運算符	描述	示例
==	檢查兩個操作數的值是否相等，如果是的話那麼條件為真	(A == B) 結果不為 true.
!=	檢查兩個操作數的值是否相等，如果值不相等，則條件變為真	(A != B) 結果為 true.
>	檢查左邊的操作數的值大於是否右操作數的值，如果是的話那麼條件為真	(A > B) 結果不為 true.
<	檢查左邊的操作數的值是否小於右操作數的值，如果是的話那麼條件為真	(A < B) 結果為 true.
>=	檢查左邊的操作數的值是否大於或等於右操作數的值，如果是的話那麼條件為真	(A >= B) 結果不為 true.
<=	檢查左邊的操作數的值是否小於或等於右操作數的值，如果是的話那麼條件為真	(A <= B) 結果為 true.

例子

試試下麵的例子就明白了所有的在C＃中使用關係運算符：

using System;

class Program
{
  static void Main(string[] args)
  {
      int a = 21;
      int b = 10;
      
      if (a == b)
      {
          Console.WriteLine("Line 1 - a is equal to b");
      }
      else
      {
          Console.WriteLine("Line 1 - a is not equal to b");
      }
      if (a < b)
      {
          Console.WriteLine("Line 2 - a is less than b");
      }
      else
      {
          Console.WriteLine("Line 2 - a is not less than b");
      }
      if (a > b)
      {
          Console.WriteLine("Line 3 - a is greater than b");
      }
      else
      {
          Console.WriteLine("Line 3 - a is not greater than b");
      }
      /* Lets change value of a and b */
      a = 5;
      b = 20;
      if (a <= b)
      {
         Console.WriteLine("Line 4 - a is either less than or equal to  b");
      }
      if (b >= a)
      {
         Console.WriteLine("Line 5-b is either greater than or equal to b");
      }
  }
}

讓我們編譯和運行上麵的程序，這將產生以下結果：

Line 1 - a is not equal to b
Line 2 - a is not less than b
Line 3 - a is greater than b
Line 4 - a is either less than or equal to b
Line 5 - b is either greater than or equal to b