选择案例

当许多不同的条件成为可能时,可以使用 Select Case。从上到下检查条件,只执行匹配的第一个案例。

Sub TestCase()
    Dim MyVar As String

    Select Case MyVar    'We Select the Variable MyVar to Work with
        Case "Hello"     'Now we simply check the cases we want to check
            MsgBox "This Case"
        Case "World"
            MsgBox "Important"
        Case "How"
            MsgBox "Stuff"
        Case "Are"
            MsgBox "I'm running out of ideas"
        Case "You?", "Today"  'You can separate several conditions with a comma
            MsgBox "Uuuhm..." 'if any is matched it will go into the case
        Case Else             'If none of the other cases is hit
            MsgBox "All of the other cases failed"
    End Select

    Dim i As Integer
    Select Case i
        Case Is > 2 '"Is" can be used instead of the variable in conditions.
            MsgBox "i is greater than 2"
        'Case 2 < Is '"Is" can only be used at the beginning of the condition.
        'Case Else is optional
    End Select
End Sub

Select Case 块的逻辑可以反转以支持不同变量的测试,在这种情况下我们也可以使用逻辑运算符:

Dim x As Integer
Dim y As Integer

x = 2
y = 5

Select Case True
    Case x > 3
        MsgBox "x is greater than 3"
    Case y < 2
        MsgBox "y is less than 2"
    Case x = 1
        MsgBox "x is equal to 1"
    Case x = 2 Xor y = 3
        MsgBox "Go read about ""Xor"""
    Case Not y = 5
        MsgBox "y is not 5"
    Case x = 3 Or x = 10
        MsgBox "x = 3 or 10"
    Case y < 10 And x < 10
        MsgBox "x and y are less than 10"
    Case Else
        MsgBox "No match found"
End Select

Case 语句也可以使用算术运算符。如果算术运算符用于 Select Case 值,则应在 Is 关键字前面:

Dim x As Integer

x = 5

Select Case x
    Case 1
        MsgBox "x equals 1"
    Case 2, 3, 4
        MsgBox "x is 2, 3 or 4"
    Case 7 To 10
        MsgBox "x is between 7 and 10 (inclusive)"
    Case Is < 2
        MsgBox "x is less than one"
    Case Is >= 7
        MsgBox "x is greater than or equal to 7"
    Case Else
        MsgBox "no match found"
End Select