VB.Net - 比較運(yùn)算符

下表顯示了VB.Net支持的所有比較運(yùn)算符。 假設(shè)變量A為10，變量B為20，則：

 條件運(yùn)算的結(jié)果應(yīng)該為true或者false，以上不返回true的都返回false！以下if語句也只有在條件為true的情況時(shí)才會(huì)執(zhí)行！

嘗試以下示例來了解VB.Net中提供的所有關(guān)系運(yùn)算符：

Module 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

當(dāng)上述代碼被編譯和執(zhí)行時(shí)，它產(chǎn)生以下結(jié)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

除了上述，VB.Net提供了三個(gè)比較運(yùn)算符，我們將在以后的章節(jié)中使用; 不過，我們?cè)谶@里給出一個(gè)簡(jiǎn)短的描述。

1、Is 運(yùn)算符 -它比較兩個(gè)對(duì)象引用變量，并確定兩個(gè)對(duì)象引用是否引用相同的對(duì)象，而不執(zhí)行值比較。 如果object1和object2都引用完全相同的對(duì)象實(shí)例，則返回結(jié)果為True; 否則，返回結(jié)果為False。

2、IsNott 運(yùn)算符 - 它還比較兩個(gè)對(duì)象引用變量，并確定兩個(gè)對(duì)象引用是否引用不同的對(duì)象。 如果object1和object2都引用完全相同的對(duì)象實(shí)例，則返回結(jié)果為False; 否則，返回結(jié)果為True。

3、Like 運(yùn)算符 - 它將字符串與模式進(jìn)行比較。