分支语句
1 If expression1 Then 2 expressions 3 ElseIf expression2 Then 4 expressions 5 Else 6 expression 7 End If
注：VBA中等于号和赋值符号都是"=",但并不会冲突，只有在选择语句中“=”才表示是否相等
示例（交互型）
1、写好程序
2、设置动作 (View-->Toolbars-->Form Controls-->Toggle Design Mode-->Push Button)
3、绑定对应的宏 (Controls-->Events-->Mouse button pressed-->Macro-->想绑定的Macro)
代码
1 Option Explicit ‘设置变量必须先定义才能使用’ 2 Option VBASupport 1 ‘必须写，使得VBA能够在LibreOffice中起作用’ 3 Sub Main 4 Dim A As Double 5 Dim B As Double 6 Dim C As Double 7 Dim detal As Double 8 A = ActiveSheet.Cells(4,2) 9 B = ActiveSheet.Cells(5,2) 10 C = ActiveSheet.Cells(6,2) 11 detal = B ^ 2 - 4 * A * C 12 13 Dim x1 As Double 14 Dim x2 As Double 15 ActiveSheet.Cells(10,2) = "" 16 ActiveSheet.Cells(11,2) = "" 17 If detal > 0 Then 18 MsgBox("two solution!") 19 x1 = (-B + sqr(detal)) / (2 * A) 20 x2 = (-B - sqr(detal)) / (2 * A) 21 ActiveSheet.Cells(10,2) = x1 22 ActiveSheet.Cells(11,2) = x2 23 Elseif detal = 0 Then 24 MsgBox("one solution!") 25 x1 = -B / (2 * A) 26 x2 = x1 27 ActiveSheet.Cells(10,2) = x1 28 ActiveSheet.Cells(11,2) = x2 29 Else 30 MsgBox("no solution!") 31 ActiveSheet.Cells(10,2) = "no solution" 32 ActiveSheet.Cells(11,2) = "no solution" 33 End if 34 End Sub 35 36 Sub clear 37 ActiveSheet.Cells(4,2) = "" 38 ActiveSheet.Cells(5,2) = "" 39 ActiveSheet.Cells(6,2) = "" 40 ActiveSheet.Cells(10,2) = "" 41 ActiveSheet.Cells(11,2) = "" 42 End sub
效果图
