vb教程编程实例详解pdf_vb程序设计教程答案第四版

实验8-7

在教学篇例8.7的基础上增加“修改确定”按钮以及用于定位记录的按钮面板，如图2.8.5所示，并编写时间过程。

解题，代码如下：

先建立标准模块，代码是：

Type studtype iNo As Integer strName As String * 20 strSex As String * 1 sMark As Single End Type

再在窗体上建立相应的按钮等控件，窗体代码如下：

Dim Student As studtype Dim Record_No As Integer Sub Form_Load() Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Label1.Caption = LOF(1) / Len(Student) Close #1 If Label1.Caption <> “0” Then Command3_Click ‘记录不为零，就显示第一条记录 End Sub

Sub Command1_Click() ‘追加记录 With Student .iNo = Val(Text1.Text) .strName = Text2.Text .strSex = IIf(Option1.Value, “1”, “0”) .sMark = Val(Text3.Text) End With

Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = LOF(1) / Len(Student) + 1 Label1.Caption = Record_No Text4.Text = Record_No ‘加这句，当场修改记录就不用手工输入了 Put #1, Record_No, Student Close #1 End Sub

Sub Command2_Click() ‘显示记录 Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = Val(Text4.Text) Get #1, Record_No, Student Text1.Text = Student.iNo Text2.Text = Student.strName If Student.strSex = “1” Then Option1.Value = True Else Option2.Value = True End If Text3.Text = Student.sMark Record_No = LOF(1) / Len(Student) Close #1 End Sub

Private Sub Command3_Click() ‘第一条记录 Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = 1 Get #1, Record_No, Student Text1.Text = Student.iNo Text2.Text = Student.strName If Student.strSex = “1” Then Option1.Value = True Else Option2.Value = True End If Text3.Text = Student.sMark Text4.Text = “1” Close #1

End Sub Private Sub Command4_Click() ‘下一条记录 If Record_No = Val(Label1.Caption) Then MsgBox “已经是最后一条记录了” Exit Sub ‘已经是最后一条记录就退出。 End If

Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = Record_No + 1 Get #1, Record_No, Student Text1.Text = Student.iNo Text2.Text = Student.strName If Student.strSex = “1” Then Option1.Value = True Else Option2.Value = True End If Text3.Text = Student.sMark Text4.Text = Record_No Close #1 End Sub

Private Sub Command5_Click() ‘前一条记录 If Record_No = 1 Then MsgBox “已经是第一条记录了” Exit Sub ‘已经是第一条记录就退出。 End If

Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = Record_No – 1 Get #1, Record_No, Student Text1.Text = Student.iNo Text2.Text = Student.strName If Student.strSex = “1” Then Option1.Value = True Else Option2.Value = True End If Text3.Text = Student.sMark Text4.Text = Record_No Close #1 End Sub

Private Sub Command6_Click() ‘最后一条记录 Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = Val(Label1.Caption) Get #1, Record_No, Student Text1.Text = Student.iNo Text2.Text = Student.strName If Student.strSex = “1” Then Option1.Value = True Else Option2.Value = True End If Text3.Text = Student.sMark Text4.Text = Label1.Caption Close #1 End Sub

Sub Command7_Click() ‘修改记录 With Student .iNo = Val(Text1.Text) .strName = Text2.Text .strSex = IIf(Option1.Value, “1”, “0”) .sMark = Val(Text3.Text) End With

Open “C:\STUDENT.DAT” For Random As #1 Len = Len(Student) Record_No = Val(Text4.Text) Put #1, Record_No, Student Close #1 End Sub

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