<ComboBox Name="cbForms" SelectionChanged="cbForms_SelectionChanged" HorizontalAlignment="Left" Margin="10,289,0,0" VerticalAlignment="Top" Width="139">
            <ComboBoxItem IsSelected="True">Polygon</ComboBoxItem>
            <ComboBoxItem>Rechteck</ComboBoxItem>
            <ComboBoxItem>Dreieck</ComboBoxItem>
            <ComboBoxItem>Kreis</ComboBoxItem>
        </ComboBox>

private void cbForms_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string text = cbForms.Text;
            switch (text)
            {
                case "Polygon":
                    {
                        commandText = "SELECT f.bezeichnung, t.X, t.Y, t.id FROM figure05 f, TABLE(SDO_UTIL.GETVERTICES(f.shape)) t";
                        lblAnz.Content = anzPolygon.ToString();
                        break;
                    }