Developing Web Applications with ASP.NET MVC3 and Entity Framework 4.1

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;

namespace Demo.Models.Domain
{
    public partial class Order
    {
        #region Primitive Properties
    
        public virtual int OrderID
        {
            get;
            set;
        }
    
        public virtual Nullable<System.DateTime> OrderDate
        {
            get;
            set;
        }
    
        public virtual Nullable<System.DateTime> RequiredDate
        {
            get;
            set;
        }
    
        public virtual Nullable<System.DateTime> ShippedDate
        {
            get;
            set;
        }
    
        public virtual Nullable<decimal> Freight
        {
            get;
            set;
        }
    
        public virtual string ShipName
        {
            get;
            set;
        }
    
        public virtual string ShipAddress
        {
            get;
            set;
        }
    
        public virtual string ShipCity
        {
            get;
            set;
        }
    
        public virtual string ShipRegion
        {
            get;
            set;
        }
    
        public virtual string ShipPostalCode
        {
            get;
            set;
        }
    
        public virtual string ShipCountry
        {
            get;
            set;
        }

        #endregion
        #region Navigation Properties
    
        public virtual Customer Customer
        {
            get { return _customer; }
            set
            {
                if (!ReferenceEquals(_customer, value))
                {
                    var previousValue = _customer;
                    _customer = value;
                    FixupCustomer(previousValue);
                }
            }
        }
        private Customer _customer;

        #endregion
        #region Association Fixup
    
        private void FixupCustomer(Customer previousValue)
        {
            if (previousValue != null && previousValue.Orders.Contains(this))
            {
                previousValue.Orders.Remove(this);
            }
    
            if (Customer != null)
            {
                if (!Customer.Orders.Contains(this))
                {
                    Customer.Orders.Add(this);
                }
            }
        }

        #endregion
    }
}