Option Explicit
 
  Dim FNr As Long
  Dim Data() As Byte
  Dim FileNameIn As String
 
 
Private Sub Command2_Click()
With CommonDialog1
    .CancelError = True
    .Filter = "Test|*.dat|"
    .ShowOpen
   End With
 
    FileNameIn = CommonDialog1.FileName
 
    FNr = FreeFile
    Open FileNameIn For Binary Access Read As #FNr
    ReDim Data(0 To (LOF(FNr) - 1))
 
    Get #FNr, , Data
 
    ' Zum 7.Byte gehen und auslesen
     Text1.Text = Hex$(Data(7))
 
    Close #FNr
End Sub
 
 
' im 7. Bytes der Datei Schreiben und abspeichern
Private Sub Command4_Click()
 
    Open App.Path & "\test.dat" For Binary Access Write As #FNr
 
    Data(7) = CLng("&H" & Text1.Text)
    Put #FNr, , Data
 
  Close #FNr    
End Sub

Imports System
Imports System.IO
Imports System.Text
Imports Microsoft.VisualBasic
 
Public Class Form1
    Inherits System.Windows.Forms.Form
    Dim VB6 As New Object
 
    Dim FNr As Long
    Dim Data() As Byte
    Dim FileNameIn As String
 
 
 
    'Read
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
 
        FNr = FreeFile()
        FileNameIn = "C:\Palette.dat"
        FileOpen(FNr, FileNameIn, FileMode.OpenOrCreate)
        ReDim Data(0 To (LOF(FNr) - 1))
 
        Get FNr, , Data <-- HIER IST UNTERSTRICHEN
 
        Label1.Text = Hex(Data(0))
        Label2.Text = Hex(Data(2))
        Label3.Text = Hex(Data(3))
        Label4.Text = Hex(Data(4))
        Label5.Text = Hex(Data(5))
 
        FileClose(FNr)
    End Sub
 
 
 
 
    'Write
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button2.Click
        FileOpen(FNr, "C:\Palette_MOD.dat", FileMode.OpenOrCreate)
 
        Data(7) = CLng("&H" & TextBox1.Text)
 
        Put FNr, , Data <-- HIER IST UNTERSTRICHEN
        FileClose(FNr)
    End Sub
End Class