Option Explicit

Private Declare Function OemToChar Lib "user32" Alias _
      "OemToCharA" (ByVal lpszSrc As String, ByVal _
      lpszDst As String) As Long

Private Sub cmdOpen_Click()
  Konvert_ASCII_ANSI False
End Sub

Private Sub cmdKonvert_Click()
  Konvert_ASCII_ANSI True
End Sub

Sub Konvert_ASCII_ANSI(konvert As Boolean)
  Dim strZeile As String
  Dim f As Integer

  f = FreeFile

  CDialogOpen.Filter = "Text-Dateien (*.txt)|*.txt"
  CDialogOpen.FileName = vbNullString
  CDialogOpen.InitDir = App.Path
  CDialogOpen.ShowOpen

  If CDialogOpen.FileName <> vbNullString Then
     Text1.Text = ""
     Open CDialogOpen.FileName For Input As #f
     While Not EOF(f)
        Line Input #f, strZeile
        If konvert Then OemToChar strZeile, strZeile
        Text1.Text = Text1.Text & vbCrLf & strZeile
     Wend
     Close #f
  End If
End Sub