VB.Net比較運算符

下表顯示了VB.Net支持的所有比較運算符。假設變數A=10，變數B=20，則：

除此之外，VB.Net還提供了三個比較運算符，我們將在以後的章節中使用它們。 但是，在這裏給出一個簡短的描述。

• Is運算符 - 它比較兩個對象引用變數，並確定兩個對象引用是否引用同一個對象而不執行值比較。 如果object1和object2都引用完全相同的對象實例，則結果為True; 否則，結果為False。
• IsNot運算符 - 它還比較兩個對象引用變數，並確定兩個對象引用是否引用不同的對象。 如果object1和object2都引用完全相同的對象實例，則結果為False; 否則，結果為True。
• Like運算符 - 它將字串與模式進行比較。

示例

嘗試下麵的例子來理解VB.Net中可用的所有關係運算符：

Module comparison_operators
   Sub Main()
      Dim a As Integer = 21
      Dim b As Integer = 10
      If (a = b) Then
          Console.WriteLine("Line 1 - a is equal to b")
      Else
          Console.WriteLine("Line 1 - a is not equal to b")
      End If
      If (a < b) Then
          Console.WriteLine("Line 2 - a is less than b")
      Else
          Console.WriteLine("Line 2 - a is not less than b")
      End If
      If (a > b) Then
          Console.WriteLine("Line 3 - a is greater than b")
      Else
          Console.WriteLine("Line 3 - a is not greater than b")
      End If
      ' Lets change value of a and b '
      a = 5
      b = 20
      If (a <= b) Then
          Console.WriteLine("Line 4 - a is either less than or equal to  b")
      End If
      If (b >= a) Then
          Console.WriteLine("Line 5 - b is either greater than  or equal to b")
      End If
      Console.ReadLine()
   End Sub
End Module

執行上面示例代碼，得到以下結果 -

F:\worksp\vb.net\operators>vbc comparison_operators.vb
F:\worksp\vb.net\operators>comparison_operators.exe
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