Private Sub txtAdresse_KeyDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyEventArgs) Handles txtAdresse.KeyDown
        If e.KeyCode = Keys.Enter Then
            ' Deine Sub
        End If
 
        Select Case e.KeyCode
            Case Asc("0") To Asc("9")
            Case Asc("A") To Asc("F")
            Case Asc("a") To Asc("f")
            Case Asc(vbBack)
            Case Else
                e.SuppressKeyPress = True
        End Select
    End Sub