OrderRepository.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;

namespace CustomAppearance {
    public class OrderRepository {
        readonly BindingList<Order> orders;

        public OrderRepository() {
            this.orders = new BindingList<Order>();
        }

        public BindingList<Order> Orders {
            get { return orders; }
        }
    }

    public class TestOrderRepository : OrderRepository {

        const int orderCount = 100;
        readonly List<Product> products;
        readonly Random random;

        public TestOrderRepository() : base() {
            this.random = new Random((int)DateTime.Now.Ticks);
            this.products = new List<Product>();

            GenerateProducts();

            for (int i = 0; i < orderCount; i++)
                Orders.Add(GenerateOrder(i));
        }

        Order GenerateOrder(int number) {
            Order order = new Order(new DateTime(2020, 1, 1).AddDays(random.Next(0, 60)),
                number % 3 == 0, RandomItem<Product>(products), random.Next(1, 100));
            return order;
        }

        T RandomItem<T>(IList<T> list) {
            int index = (int)(random.NextDouble() * 0.99 * (list.Count));
            return list[index];
        }

        void GenerateProducts() {
            products.Add(new Product("Tofu", 50));
            products.Add(new Product("Chocolade", 34));
            products.Add(new Product("Ikura", 70));
            products.Add(new Product("Chai", 3));
            products.Add(new Product("Boston Crab Meat", 36));
            products.Add(new Product("Ravioli Angelo", 18));
            products.Add(new Product("Ipon Coffee", 10));
            products.Add(new Product("Queso Cabrales", 25));
        }
    }
}