第八章数据文件.pptVIP

例8.6 编写学生信息管理程序 添加标准模块，定义变量 Type StudType iNo As Integer strName As String * 20 strSex As String * 1 sMark As Single End Type 在窗体编辑程序 Dim Student As StudType Dim Record_No As Integer Sub Form_Load() Open C:\STUDENT.DAT For Random As #1 Len = Len(Student) Label2.Caption = LOF(1) / Len(Student) Close #1 End Sub Sub Command1_Click() 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 Label2.Caption = 总记录数: Record_No Put #1, Record_No, Student Close #1 End Sub Sub Command2_Click() 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 Close #1 End Sub 例:以下叙述中错误的是 A) 顺序文件中的数据只能按顺序读写 B)对同一个文件，可以用不同的文件号打开 C)执行Close 语句，可将文件缓冲区中的数据写 到文件中 D)随机文件中各记录的长度是随机的 在窗体上有Text1、Tex2两个文本框，一个Command1命令按钮。运行后窗体外观如图 设如下变量 Private Type Person name As String*8 major As String*20 End Type Dim p As Person 设文本框中的数据已正确地赋值给Person类型的变量p，当单击“保存”按钮时，能够正确地把变量中的数据写入随机文件Text2.dat中的程序段是： A) Open C:\Text2.dat For Output As #1 Put #1,1,p Close #1 B)Open C:\Text2.dat For Random As #1 Get #1,1,p Close #1 C)Open C:\Text2.dat For Random As #1 Len=Len(p) Put #1,1,p Close #1 D)Open C:\Text2.dat For Random As #1 Len=Len(p) Get #1,1,p Close #1 8.4 二进制访问模式 二进制访问模式与随机访问模式类似，读写语句也是Get和Put，区别在于二进制模式的访问单位是字节，而随机模式的访问单位是记录 例如: Open C:\Student.Dat For Binary As # 1 例8.7 编写一个文件复制程序 Private Sub Form_Click() Dim char As Byte Dim FileNum1%, FileNum2% FileNum1 = FreeFile Open C:\S.Dat For Binary As #FileNum1 FileNum2 = FreeFile Open C:\S.Bak For Binary As #FileNum2 Do