VB程序設計教程(第四版)龔沛曾-實驗8-7

實驗8-7

在教學篇例8.7的基礎上增加“修改確定”按鈕以及用於定位記錄的按鈕面板，如圖2.8.5所示，並編寫時間過程。

解題，代碼如下：

先建立標準模塊，代碼是：

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

再在窗體上建立相應的按鈕等控件，窗體代碼如下：

 

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 '記錄不爲零，就顯示第一條記錄
End Sub

Sub Command1_Click() '追加記錄
    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 '加這句，當場修改記錄就不用手工輸入了
    Put #1, Record_No, Student
    Close #1
End Sub

Sub Command2_Click() '顯示記錄
    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() '第一條記錄
    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() '下一條記錄
    If Record_No = Val(Label1.Caption) Then
        MsgBox "已經是最後一條記錄了"
        Exit Sub   '已經是最後一條記錄就退出。
    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() '前一條記錄
    If Record_No = 1 Then
        MsgBox "已經是第一條記錄了"
        Exit Sub '已經是第一條記錄就退出。
    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() '最後一條記錄
    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() '修改記錄
    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