参考下：

计算器的程序，很简单，只弄了+-法，乘除没弄，只要把代码看懂照着+-法改一下就行了,不过涉及到多级运算只用一个LastClick是不行的

程序的控件就两种

CommandBotton和TextBox都是最基本的

先创建十一个CommandBotton，Caption改为0-9以及一个"."(小数点)

创建三个CommandBotton，Caption改为“-”，“+”“=”

创建五个CommandBotton，Caption改为“CM”(clearmemory) “MR”(memoryrecall) “MS”(memorysave) “C”(clear) “AC”(allclear)

再创建个TextBox

下面的是对应代码，很清楚

不懂来问我`~

Dim Counter As Double ‘这个用来记录结果

Dim Memory As Double ‘用来记录你保存的数，这个我们用的科学计算器里也有

Dim Reg As Double ‘这个也是用来记录结果

Dim CalcNumber As Long ‘这个是判断：1当之前点过一次+或-时再点一次运算结果，2如果前面没点过+或-则不进行运算

Dim DisplayFromNew As Boolean ‘这个用来判断输入框状态：是接着输入还是从新输入新的数

Dim AlreadyDecimalThere As Boolean ‘这个用来判断是否能用小数点

Dim LastClick As String ‘这个用来记录最后一次选择的运算法则

Private Sub Form_Load()

Display.Text = "0"

Reg = 0

CalcNumber = 0

DisplayFromNew = True

AlreadyDecimalThere = False

End Sub

Private Sub AllClear_Click() ‘这个不用说了，是全部清空

DisplayFromNew = True ‘恢复到初始状态

Counter = 0

Display.Text = "0" ‘清空输入框

CalcNumber = 0

Reg = 0

AlreadyDecimalThere = False ‘恢复到初始状态

End Sub

Private Sub Clear_Click() ‘清空，但不清空纪录

DisplayFromNew = True

Display.Text = "0"

End Sub

Private Sub ClearMemory_Click() ‘清空纪录

Memory = 0

End Sub

Private Sub Decimal_Click() ‘关于小数点的

If AlreadyDecimalThere = False Then

AddDisplayDigit "."

AlreadyDecimalThere = True ‘每次输入只能输一次小数点

End If

End Sub

Private Sub Equals_Click() ‘等号时的

If LastClick = "Minus" Then

If CalcNumber = 0 Then

Reg = CDbl(Display.Text) ‘记录

DisplayFromNew = True

CalcNumber = 1

Else ‘这个的意思是，如果只点了法则(+或-)之后没点数，就加上前面输的数，但我觉得这样就等于前面输得数的2倍(+时)或0(-时)，所以不用这么麻烦

Counter = Reg - CDbl(Display.Text)

Display.Text = CStr(Counter)

DisplayFromNew = True

AlreadyDecimalThere = False

Reg = CDbl(Display.Text)

End If

ElseIf LastClick = "Addition" Then ‘这是加法，和减法一样

If CalcNumber = 0 Then

Reg = CDbl(Display.Text)

DisplayFromNew = True

CalcNumber = 1

Else

Counter = Reg + CDbl(Display.Text)

Display.Text = CStr(Counter)

DisplayFromNew = True

AlreadyDecimalThere = False

Reg = CDbl(Display.Text)

End If

End If

CalcNumber = 0

End Sub

Sub AddDisplayDigit(Addition As String) ‘这一段十分重要，也是大家要学习的，就是自己创建一个函数，这样应用起来会十分方便

If DisplayFromNew = True Then

Display.Text = Addition ‘当DisplayFromNew = True时(大家注意杂那几种情况下= True)输入栏从新显示刚输入的数

DisplayFromNew = False ‘之后立即变为False，因为要接着这个数继续输入

Else

Display.Text = Display.Text & Addition ‘当DisplayFromNew = False 就是接着输入栏里已有的数字继续输入

End If

End Sub

注：为何要弄两种情况呢，因为当点击-或+时，要求输入栏从新记录

Private Sub MemorySave_Click() ‘这是保存记录

If DisplayFromNew = False Then

Memory = CDbl(Display.Text)

End If

End Sub

Private Sub MemoryRecall_Click() ‘打开纪录

Display = CStr(Memory)

End Sub

Private Sub Minus_Click() ‘点击

If CalcNumber = 0 Then

Reg = CDbl(Display.Text)

DisplayFromNew = True

CalcNumber = 1

Else ‘这个就是如果前面输过一次-号，再点-号就运算结果，这一点是很重要的，如果不加这个就无法进行连续运算 Counter = Reg - CDbl(Display.Text)

Display.Text = CStr(Counter)

DisplayFromNew = True

AlreadyDecimalThere = False

Reg = CDbl(Display.Text)

End If

LastClick = "Minus"

End Sub

Private Sub Plus_Click() ‘和减法一样

If CalcNumber = 0 Then

Reg = CDbl(Display.Text)

DisplayFromNew = True

CalcNumber = 1

Else

Counter = Reg + CDbl(Display.Text)

Display.Text = CStr(Counter)

DisplayFromNew = True

AlreadyDecimalThere = False

Reg = CDbl(Display.Text)

End If

LastClick = "Addition"

End Sub

‘下面的就简单了0-9，不过用到了前面定义的函数AddDisplayDigit，大家看到这个自定义函数的作用了吧

Private Sub Nine_Click()

AddDisplayDigit "9"

End Sub

Private Sub Eight_Click()

AddDisplayDigit "8"

End Sub

Private Sub Seven_Click()

AddDisplayDigit "7"

End Sub

Private Sub Six_Click()

AddDisplayDigit "6"

End Sub

Private Sub Five_Click()

AddDisplayDigit "5"

End Sub

Private Sub Four_Click()

AddDisplayDigit "4"

End Sub

Private Sub Three_Click()

AddDisplayDigit "3"

End Sub

Private Sub Two_Click()

AddDisplayDigit "2"

End Sub

Private Sub One_Click()

AddDisplayDigit "1"

End Sub

Private Sub Zero_Click()

AddDisplayDigit "0"

End Sub