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  • vb.net亚博优惠活动之二进制文件的读写操作

  • 2015-01-18 13:40 来源:未知
二进制文件的读写操作(相关vb.net亚博优惠活动)
二进制文件的打开也用fileopen完成,只是打开二进制文件的形式为:openmode.binary
读取二进制文件用的是fileget方法,写入二进制文件用的是fileput方法。
应用实例:将一批随机数保存在一个dat文件中,然后再将其提取到文本框中。[实验报告 39]
见,二进制文件的读写一批随机数的存取,程序为:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
??????? Dim x, i, fn As Integer
??????? Dim s As String = ""
??????? fn = FreeFile()
??????? FileOpen(fn, "d:\data.dat", OpenMode.Binary)
??????? For i = 1 To 8
??????????? x = Int(Rnd() * 100)
??????????? s = s + Str(x)
?????????? ?FilePut(fn, x)
??????? Next
??????? FileClose(fn)
??????? TextBox1.Text = s
??? End Sub
?
??? Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
??????? Dim x, fn As Integer
??????? Dim s As String = ""
??????? fn = FreeFile()
??????? FileOpen(fn, "d:\data.dat", OpenMode.Binary)
??????? Do While Not EOF(fn)
??????????? FileGet(fn, x)
??????????? s = s + Str(x) + " "
??????? Loop
??????? FileClose(fn)
??????? TextBox1.Text = s
??? End Sub
说明:此时形成的文件data.dat如果打开查看,内容是乱码。因为它是以二进制的形式存放的。即使将文件名换成da.txt,结果也是一样不能查看内容。
应用实例:演示二进制文件以字节为单位的复制过程。[实验报告 40]
见,二进制文件以字节为单位的复制过程,程序为:
Public Class Form1
??? Dim s As String
??? Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
??????? OpenFileDialog1.ShowDialog()
??????? s = OpenFileDialog1.FileName
??????? TextBox1.Text = s
??? End Sub
?
??? Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
??????? Dim fa, fb As String
??????? Dim a, b, len, k As Integer
??????? Dim byt As Byte
??????? ' Try
??????? fa = TextBox1.Text : fb = TextBox2.Text
??????? a = FreeFile()
??????? FileOpen(a, fa, OpenMode.Binary)
??????? b = FreeFile()
??????? FileOpen(b, fb, OpenMode.Binary)
??????? len = LOF(a)
??????? For k = 1 To len
??????????? FileGet(a, byt)
??????????? FilePut(b, byt)
??????????? ProgressBar1.Value = 100 * k \ len
??????? Next
??????? FileClose(a)
??????? FileClose(b)
?? ?????ss = "文件复制完成!" & "文件长度为:" & len & "字节"
??????? MsgBox(ss, 16, "注意")??????
?End
??????? 'Catch ex As Exception
??????? 'MsgBox(ex.Message, MsgBoxStyle.OkOnly, "error")
??????? ' End Try
??? End Sub
End Class
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