Dim myEingabe As String
Dim bOK As Boolean
Dim I As Long
 
Do
  myEingabe = InputBox("Ihre Eingabe:", "Eingabe", myEingabe)
  If myEingabe <> "" Then
    <font color=green>' Prüfen, ob unzulässige Zeichen enthalten</font>
    bOK = True
    For I = 1 To Len(myEingabe)
      Select Case Asc(Mid(myEingabe, I, 1))
        Case 0 To 57, 65 To 90, 97 To 122
        Case Else
          bOK = False: Exit For
      End Select
    Next I
    If bOK Then Exit Do
  End If
Loop Until myEingabe = ""
 
If myEingabe <> "" Then
  <font color=green>' Eingabe ist OK</font>
  ....
End If

Dim F As Integer
Dim sLine As String
Dim sNew As String
Diim sFilename As String
Dim I As Long
 
sFilename = "DeineTextdatei.txt"
F = FreeFile
Open sFilename For Input As #F
While Not Eof(F)
  Line Input #F, sLine
  <font color=green>' unzulässige Zeichen entfernen</font>
  sNew = ""
  For I = 1 To Len(sLine)
    Select Case Asc(Mid(sLine, I, 1))
      Case 44, 45, 46  <font color=green>' usw.</font>
      Case Else
        sNew = sNew & Mid(sLine, I, 1))
    End Select
  Next I
 
  <font color=green>' Zeile der ListBox hinzufügen</font>
  List1.AddItem sNew
Wend
Close #F