Private Sub TextBox1_KeyPress(ByVal sender As System.Object, _
ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        Select Case e.KeyChar
            Case ChrW(Asc("0")) To ChrW(Asc("9")), ChrW(8), ChrW(32), ChrW(Asc( _
              ","), ChrW(Asc("+"), ChrW(Asc("/"),
            Case Else
                e.KeyChar = ChrW(0)
                My.Computer.Audio.Play("C:\WINDOWS\Media\Windows" & _
                  "XP-Fehler.wav", AudioPlayMode.Background)
        End Select
    End Sub