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 private void ComboBox_Loaded(object sender, RoutedEventArgs e)
        {
            cb.Items.Add("Antarktika");
            cb.Items.Add("Nordamerika");
            cb.Items.Add("Südamerika");

            Debug.Print($"Aktuelle Anzahl der Elemente : {cb.Items.Count}");
            for (int i = 0; i < cb.Items.Count; i++)
            {
                Debug.Print($"  > Schleifenzähler          : {i}");
                Debug.Print($"  > Element                  : {cb.Items[i]}");
                Debug.Print($"  > Typ                      : {cb.Items[i].GetType()}");
                // Ausgabe : > Typ             : System.String

                ComboBoxItem ci = cb.Items[i] as ComboBoxItem; // Kein ComboBoxItem!!!
                Debug.Print($"  > ComboBoxItem             : {(ci != null)}");
                if (ci != null)
                {
                    if (i % 2 == 0)
                    {
                        ci.Background = Brushes.Red;
                    }
                    else
                    {
                        ci.Background = Brushes.Yellow;
                    }
                }

                Debug.Print(new String('-', 50));
            }

            // Alternative
            AddNewComboboxItem("Europa", Brushes.Red);
            AddNewComboboxItem("Asien", Brushes.Yellow);
            AddNewComboboxItem("Afrika", Brushes.Red);
            AddNewComboboxItem("Australien", Brushes.Yellow);
        }

        private void AddNewComboboxItem(string content, Brush brushes)
        {
            ComboBoxItem newItem = new ComboBoxItem();
            newItem.Content = content;
            newItem.Background = brushes;

            cb.Items.Add(newItem);
        }
    }