Public Class SimpleCalculator
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Inherits System.Windows.Forms.Form
#Region " Windows 窗体设计器生成的代码 "
Public Sub New()
MyBase.New()
'该调用是 Windows 窗体设计器所必需的。
InitializeComponent()
'在 InitializeComponent() 调用之后添加任何初始化
End Sub
'窗体重写处置以清理组件列表。
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub
'Windows 窗体设计器所必需的
Private components As System.ComponentModel.IContainer
'注意：以下过程是 Windows 窗体设计器所必需的
'可以使用 Windows 窗体设计器修改此过程。
'不要使用代码编辑器修改它。
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
Friend WithEvents Button1 As System.Windows.Forms.Button
Friend WithEvents Button2 As System.Windows.Forms.Button
Friend WithEvents Button3 As System.Windows.Forms.Button
Friend WithEvents Button4 As System.Windows.Forms.Button
Friend WithEvents Button5 As System.Windows.Forms.Button
Friend WithEvents Button6 As System.Windows.Forms.Button
Friend WithEvents Button7 As System.Windows.Forms.Button
Friend WithEvents Button8 As System.Windows.Forms.Button
Friend WithEvents Button9 As System.Windows.Forms.Button
Friend WithEvents Button10 As System.Windows.Forms.Button
Friend WithEvents Button11 As System.Windows.Forms.Button
Friend WithEvents Button12 As System.Windows.Forms.Button
Friend WithEvents Button13 As System.Windows.Forms.Button
Friend WithEvents Button14 As System.Windows.Forms.Button
Friend WithEvents Button15 As System.Windows.Forms.Button
Friend WithEvents Button16 As System.Windows.Forms.Button
System.Diagnostics.DebuggerStepThrough() Private Sub InitializeComponent()
Me.Label1 = New System.Windows.Forms.Label
Me.TextBox1 = New System.Windows.Forms.TextBox
Me.Button1 = New System.Windows.Forms.Button
Me.Button2 = New System.Windows.Forms.Button
Me.Button3 = New System.Windows.Forms.Button
Me.Button4 = New System.Windows.Forms.Button
Me.Button5 = New System.Windows.Forms.Button
Me.Button6 = New System.Windows.Forms.Button
Me.Button7 = New System.Windows.Forms.Button
Me.Button8 = New System.Windows.Forms.Button
Me.Button9 = New System.Windows.Forms.Button
Me.Button10 = New System.Windows.Forms.Button
Me.Button11 = New System.Windows.Forms.Button
Me.Button12 = New System.Windows.Forms.Button
Me.Button13 = New System.Windows.Forms.Button
Me.Button14 = New System.Windows.Forms.Button
Me.Button15 = New System.Windows.Forms.Button
Me.Button16 = New System.Windows.Forms.Button
Me.SuspendLayout()
'
'Label1
'
Me.Label1.Location = New System.Drawing.Point(16, 16)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(48, 16)
Me.Label1.TabIndex = 0
Me.Label1.Text = "结果："
'
'TextBox1
'
Me.TextBox1.Location = New System.Drawing.Point(64, 8)
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.Size = New System.Drawing.Size(120, 21)
Me.TextBox1.TabIndex = 1
Me.TextBox1.Text = ""
'
'Button1
'
Me.Button1.Location = New System.Drawing.Point(200, 8)
Me.Button1.Name = "Button1"
Me.Button1.Size = New System.Drawing.Size(56, 24)
Me.Button1.TabIndex = 2
Me.Button1.Text = "清空"
'
'Button2
'
Me.Button2.Location = New System.Drawing.Point(48, 56)
Me.Button2.Name = "Button2"
Me.Button2.Size = New System.Drawing.Size(24, 24)
Me.Button2.TabIndex = 3
Me.Button2.Text = "1"
'
'Button3
'
Me.Button3.Location = New System.Drawing.Point(88, 56)
Me.Button3.Name = "Button3"
Me.Button3.Size = New System.Drawing.Size(24, 24)
Me.Button3.TabIndex = 4
Me.Button3.Text = "2"
'
'Button4
'
Me.Button4.Location = New System.Drawing.Point(136, 56)
Me.Button4.Name = "Button4"
Me.Button4.Size = New System.Drawing.Size(24, 24)
Me.Button4.TabIndex = 5
Me.Button4.Text = "3"
'
'Button5
'
Me.Button5.Location = New System.Drawing.Point(48, 88)
Me.Button5.Name = "Button5"
Me.Button5.Size = New System.Drawing.Size(24, 24)
Me.Button5.TabIndex = 6
Me.Button5.Text = "4"
'
'Button6
'
Me.Button6.Location = New System.Drawing.Point(88, 88)
Me.Button6.Name = "Button6"
Me.Button6.Size = New System.Drawing.Size(24, 24)
Me.Button6.TabIndex = 7
Me.Button6.Text = "5"
'
'Button7
'
Me.Button7.Location = New System.Drawing.Point(136, 88)
Me.Button7.Name = "Button7"
Me.Button7.Size = New System.Drawing.Size(24, 24)
Me.Button7.TabIndex = 8
Me.Button7.Text = "6"
'
'Button8
'
Me.Button8.Location = New System.Drawing.Point(48, 120)
Me.Button8.Name = "Button8"
Me.Button8.Size = New System.Drawing.Size(24, 24)
Me.Button8.TabIndex = 9
Me.Button8.Text = "7"
'
'Button9
'
Me.Button9.Location = New System.Drawing.Point(88, 120)
Me.Button9.Name = "Button9"
Me.Button9.Size = New System.Drawing.Size(24, 24)
Me.Button9.TabIndex = 10
Me.Button9.Text = "8"
'
'Button10
'
Me.Button10.Location = New System.Drawing.Point(136, 120)
Me.Button10.Name = "Button10"
Me.Button10.Size = New System.Drawing.Size(24, 24)
Me.Button10.TabIndex = 11
Me.Button10.Text = "9"
'
'Button11
'
Me.Button11.Location = New System.Drawing.Point(48, 152)
Me.Button11.Name = "Button11"
Me.Button11.Size = New System.Drawing.Size(24, 24)
Me.Button11.TabIndex = 12
Me.Button11.Text = "0"
'
'Button12
'
Me.Button12.Location = New System.Drawing.Point(176, 56)
Me.Button12.Name = "Button12"
Me.Button12.Size = New System.Drawing.Size(24, 24)
Me.Button12.TabIndex = 13
Me.Button12.Text = "+"
'
'Button13
'
Me.Button13.Location = New System.Drawing.Point(176, 88)
Me.Button13.Name = "Button13"
Me.Button13.Size = New System.Drawing.Size(24, 24)
Me.Button13.TabIndex = 14
Me.Button13.Text = "-"
'
'Button14
'
Me.Button14.Location = New System.Drawing.Point(176, 120)
Me.Button14.Name = "Button14"
Me.Button14.Size = New System.Drawing.Size(24, 24)
Me.Button14.TabIndex = 15
Me.Button14.Text = "*"
'
'Button15
'
Me.Button15.Location = New System.Drawing.Point(176, 152)
Me.Button15.Name = "Button15"
Me.Button15.Size = New System.Drawing.Size(24, 24)
Me.Button15.TabIndex = 16
Me.Button15.Text = "/"
'
'Button16
'
Me.Button16.Location = New System.Drawing.Point(88, 152)
Me.Button16.Name = "Button16"
Me.Button16.Size = New System.Drawing.Size(72, 24)
Me.Button16.TabIndex = 17
Me.Button16.Text = "计算"
'
'SimpleCalculator
'
Me.AutoScaleBaseSize = New System.Drawing.Size(6, 14)
Me.ClientSize = New System.Drawing.Size(264, 190)
Me.Controls.Add(Me.Button16)
Me.Controls.Add(Me.Button15)
Me.Controls.Add(Me.Button14)
Me.Controls.Add(Me.Button13)
Me.Controls.Add(Me.Button12)
Me.Controls.Add(Me.Button11)
Me.Controls.Add(Me.Button10)
Me.Controls.Add(Me.Button9)
Me.Controls.Add(Me.Button8)
Me.Controls.Add(Me.Button7)
Me.Controls.Add(Me.Button6)
Me.Controls.Add(Me.Button5)
Me.Controls.Add(Me.Button4)
Me.Controls.Add(Me.Button3)
Me.Controls.Add(Me.Button2)
Me.Controls.Add(Me.Button1)
Me.Controls.Add(Me.TextBox1)
Me.Controls.Add(Me.Label1)
Me.Name = "SimpleCalculator"
Me.Text = "简单计算器"
Me.ResumeLayout(False)
End Sub
#End Region
Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)
End Sub
Private Sub TextBox1_TabStopChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
Dim btn As Button '按钮类型的变量
btn = sender '把产生该事件的按钮对象赋值给btn
TextBox1.Text = TextBox1.Text + btn.Text '把该按钮的Text属性值连接到TextBox1中
End Sub
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button6.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button7.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button8.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button9.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button11_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button11.Click
Dim btn As Button
btn = sender
TextBox1.Text += btn.Text
End Sub
Private Sub Button12_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button12.Click
Dim btn As Button
btn = sender
'在文本框的Text属性后连接一个空格、本按钮的Text属性值和一个空格
TextBox1.Text = TextBox1.Text + " " + btn.Text + " "
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
TextBox1.Text = "" '清空文本框
End Sub
Private Sub Button13_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button13.Click
Dim btn As Button
btn = sender
TextBox1.Text = TextBox1.Text + " " + btn.Text + " "
End Sub
Private Sub Button14_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button14.Click
Dim btn As Button
btn = sender
TextBox1.Text = TextBox1.Text + " " + btn.Text + " "
End Sub
Private Sub Button15_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button15.Click
Dim btn As Button
btn = sender
TextBox1.Text = TextBox1.Text + " " + btn.Text + " "
End Sub
Private Sub Button16_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button16.Click
'发生错误转移到标号“ErrorPro”指定的行去执行错误处理程序
On Error GoTo ErrorPro
Dim r As Decimal '保存计算结果的变量
Dim t As String = TextBox1.Text '用于保存文本框中的算术表达式
Dim space As Integer = t.IndexOf(" ") '搜索空格位置,如果没有空格，返回值为0
'字符串的取子符方法，第二个参数小于0，则将产生错误号为5的异常，即过程参数不正确
Dim s1 As String = t.Substring(0, space) '通过取子串方法获得第一个运算数
Dim op As String = t.Substring(space + 1, 1) '通过取子串方法获得运算符
Dim s2 As String = t.Substring(space + 3) '通过取子串方法获得第二个运算数
Dim arg1, arg2 As Integer
arg1 = Val(s1) : arg2 = Val(s2)
Select Case op
Case "+" : r = arg1 + arg2
Case "-" : r = arg1 - arg2
Case "*" : r = arg1 * arg2
Case "/" : r = arg1 / arg2
Case Else
MsgBox("输入的运算符有误！")
Exit Sub
End Select
TextBox1.Text = CStr(r) '显示结果
Exit Sub '退出过程
ErrorPro: '错误处理程序块
Select Case Err.Number
Case 6 '除数为零时，或运算溢出时的错误号
MsgBox("算术运算溢出！", , "溢出提示")
TextBox1.Focus()
Exit Sub
Case 5 ' Substring过程的参数不符合要求的错误号
MsgBox("必须输入运算符和第二个运算数！", , "运算数少")
Exit Sub
Case Else
'其它情况显示错误号和错误原因
MsgBox("错误号为" Err.Number Chr(10) Chr(13) "错误原因：" Err.Description)
Exit Sub
End Select
End Sub
End Class
减去字符串，很简单
Dim ss1 As String
ss1 = ss1.Replace(ss2, "")
ss1.Replace(ss2, "") 的意思就是，把ss1字符串中的ss2都替换成空字符，得到的结果仍然赋给ss1
至于你那个left，VB.net似乎没有这个函数了，你写那个Left，实际是窗体的位置属性，连编译都无法编译，要取子字符串，用
ss1 = ss1.Substring(0, 1)
参数0表示从第几个字符开始，1表示取多少个字符
使用VB提供的取子串函数Mid(S,k,n)；
函数Mid(S,k,n)的功能，从指定的字符串表达式S的第k位开始取连续的n个字符。
例如：S = "1234567890"，Mid(S,1,3) ，返回"123"
例如：S = "1234567890"，Mid(S,3,7) ，返回"3456789"
等等；
结合VB的IF语句，就可以实现你的要求；
If Mid("1234567890",1,3) = "123" Then
MsgBox("正确")
Else
MsgBox("错误")
End If
可以如下截取056
Private Sub Command1_Click()
a = "123.45056"
Me.Caption = Mid(a, InStr(a, "056"), 3)
End Sub
