通过使用条件语句和循环语句 (也称为控制结构), 可以编写做出决策和重复操作的 Visual Basic 代码。 另一个有用的控制结构是With 语句, 它允许您运行一系列语句, 而无需重新限定对象。
条件语句
- If…Then…Else：当条件为 True 或 False 时执行分支语句
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11Function Bonus(performance, salary)
If performance = 1 Then
Bonus = salary * 0.1
ElseIf performance = 2 Then
Bonus = salary * 0.09
ElseIf performance = 3 Then
Bonus = salary * 0.07
Else
Bonus = 0
End If
End Function - Select Case：从一组条件中选择一个分支
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14Function Bonus(performance, salary)
Select Case performance
Case 1
Bonus = salary * 0.1
Case 2, 3
Bonus = salary * 0.09
Case 4 To 6
Bonus = salary * 0.07
Case Is > 8
Bonus = 100
Case Else
Bonus = 0
End Select
End Function
循环重复代码
- Do…Loop：当条件为 True 时开始循环或停止循环
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10Sub ExitExample()
counter = 0
myNum = 9
Do Until myNum = 10
myNum = myNum - 1
counter = counter + 1
If myNum < 10 Then Exit Do
Loop
MsgBox "The loop made " & counter & " repetitions."
End Sub - For…Next：使用计数器按指定次数运行语句
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6Sub TwosTotal()
For j = 2 To 10 Step 2
total = total + j
Next j
MsgBox "The total is " & total
End Sub - For Each…Next：对集合中的每个项目重复运行一组语句
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4Dim TestArray(10) As Integer, I As Variant
For Each I In TestArray
TestArray(I) = I
Next I对同一对象运行多个语句
- With：对同一对象运行一系列语句
Exit 语句
退出 Do…Loop 块、 For…Next 、 Function 、 Sub 或 Property 代码
- Exit Do
- Exit For
- Exit Function
- Exit Property
- Exit Sub