Private Sub myProg_KeyDown(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
        If ((e.Modifiers = Keys.Control) AndAlso (e.KeyCode = Keys.Oemplus)) _
        Then
            zoomIn()
            zeichne_neu()
        ElseIf ((e.Modifiers = Keys.Control) AndAlso (e.KeyCode = _
          Keys.OemMinus)) Then
            zoomout()
            zeichne_neu()
        End If
    End Sub