Dim opt As String


Private Sub Command1_Click()
opt = "+"
End Sub

Private Sub Command2_Click()
opt = "-"
End Sub

Private Sub Command3_Click()
opt = "*"
End Sub

Private Sub Command4_Click()
opt = "/"
End Sub

Private Sub Command5_Click()
Dim a, b, result As Double
a = Text1.Text
b = Text2.Text
Select Case opt
Case "+"
result = Val(a) + Val(b)
Case "-"
result = Val(a) - Val(b)
Case "*"
result = Val(a) * Val(b)
Case "/"
result = Val(a) / Val(b)
End Select
End Sub

[ 本帖最后由 x729400643 于 2009-8-23 22:56 编辑 ]

把opt定义为全局变量，并且在Private Sub Command5_Click()过程后把 opt的值清空。