ComboBoxPage.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace ModernWpf.SampleApp.ControlPages
{
    public partial class ComboBoxPage
    {
        public List<Tuple<string, FontFamily>> Fonts { get; } = new List<Tuple<string, FontFamily>>()
            {
                new Tuple<string, FontFamily>("Arial", new FontFamily("Arial")),
                new Tuple<string, FontFamily>("Comic Sans MS", new FontFamily("Comic Sans MS")),
                new Tuple<string, FontFamily>("Courier New", new FontFamily("Courier New")),
                new Tuple<string, FontFamily>("Segoe UI", new FontFamily("Segoe UI")),
                new Tuple<string, FontFamily>("Times New Roman", new FontFamily("Times New Roman"))
            };

        public List<double> FontSizes { get; } = new List<double>()
            {
                8,
                9,
                10,
                11,
                12,
                14,
                16,
                18,
                20,
                24,
                28,
                36,
                48,
                72
            };

        public ComboBoxPage()
        {
            InitializeComponent();

            Combo4.ItemsSource = Enumerable.Range(1, 5000).ToList();
            Combo4.SelectedIndex = 0;
        }

        private void ColorComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string colorName = e.AddedItems[0].ToString();
            Color color = default;
            switch (colorName)
            {
                case "Yellow":
                    color = Colors.Yellow;
                    break;
                case "Green":
                    color = Colors.Green;
                    break;
                case "Blue":
                    color = Colors.Blue;
                    break;
                case "Red":
                    color = Colors.Red;
                    break;
            }
            Control1Output.Fill = new SolidColorBrush(color);
        }
    }
}