Data.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel.DataAnnotations;

namespace MasterDetailInCode {
    public class Employee {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Title { get; set; }

        [Display(AutoGenerateField = false)]
        public string Notes { get; set; }
        public List<Order> Orders { get; set; }
    }
    public class Order {
        public string Supplier { get; set; }
        public DateTime Date { get; set; }
        public string ProductName { get; set; }
        public int Quantity { get; set; }
    }
    public class Employees {
        public static ObservableCollection<Employee> GetEmployees() {
            ObservableCollection<Employee> employees = new ObservableCollection<Employee>() {
                new Employee() {
                    FirstName="Bruce", 
                    LastName="Cambell", 
                    Title="Sales Manager", 
                    Notes="Education includes a BA in psychology from Colorado State University in 1970.  He also completed 'The Art of the Cold Call.'  Bruce is a member of Toastmasters International.",
                    Orders = new List<Order>()
                },
                new Employee() { 
                    FirstName="Cindy", 
                    LastName="Haneline", 
                    Title="Vice President of Sales", 
                    Notes="Cindy received her BTS commercial in 1974 and a Ph.D. in international marketing from the University of Dallas in 1981.  She is fluent in French and Italian and reads German.  She joined the company as a sales representative, was promoted to sales manager in January 1992 and to vice president of sales in March 1993.  Cindy is a member of the Sales Management Roundtable, the Seattle Chamber of Commerce, and the Pacific Rim Importers Association.",
                    Orders = new List<Order>()
                },
            };
            employees[0].Orders.Add(new Order() { Supplier = "Supplier 1", Date = DateTime.Now, ProductName = "TV", Quantity = 20 });
            employees[0].Orders.Add(new Order() { Supplier = "Supplier 2", Date = DateTime.Now.AddDays(3), ProductName = "Projector", Quantity = 15 });
            employees[0].Orders.Add(new Order() { Supplier = "Supplier 3", Date = DateTime.Now.AddDays(3), ProductName = "HDMI Cable", Quantity = 50 });
            employees[1].Orders.Add(new Order() { Supplier = "Supplier 1", Date = DateTime.Now.AddDays(1), ProductName = "Blu-Ray Player", Quantity = 10 });
            employees[1].Orders.Add(new Order() { Supplier = "Supplier 2", Date = DateTime.Now.AddDays(1), ProductName = "HDMI Cable", Quantity = 10 });
            employees[1].Orders.Add(new Order() { Supplier = "Supplier 3", Date = DateTime.Now.AddDays(1), ProductName = "Projector", Quantity = 10 });
            employees[1].Orders.Add(new Order() { Supplier = "Supplier 4", Date = DateTime.Now.AddDays(1), ProductName = "Amplifier", Quantity = 10 });
            return employees;
        }
    }
}