二進制文件的讀寫操作（相關vb.net教程)
二進制文件的打開也用fileopen完成，只是打開二進制文件的形式為：openmode.binary
讀取二進制文件用的是fileget方法，寫入二進制文件用的是fileput方法。
應用實例：將一批隨機數保存在一個dat文件中，然后再將其提取到文本框中。[實驗報告 39]
見，二進制文件的讀寫一批隨機數的存取，程序為：
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
說明：此時形成的文件data.dat如果打開查看，內容是亂碼。因為它是以二進制的形式存放的。即使將文件名換成da.txt，結果也是一樣不能查看內容。
應用實例：演示二進制文件以字節為單位的復制過程。[實驗報告 40]
見，二進制文件以字節為單位的復制過程，程序為：
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 = "文件復制完成！" & "文件長度為：" & len & "字節"
        MsgBox(ss, 16, "注意")      
 End
        'Catch ex As Exception
        'MsgBox(ex.Message, MsgBoxStyle.OkOnly, "error")
        ' End Try
    End Sub
End Class