Updating a complex object with linq and Entity Framework - linq

Question

I have an object, called Order, which has several properties which are also objects. when I update the Order object the simple properties are updated correctly, but the complex ones (which reside in different tables) are not being updated and instead new ones are created. What am I doing wrong. Also, when I try to get a multiple items property (Items in this example) it returns null and not the saved items.
Code Sample:
[DataContract]
public class Order
{
[Key]
[DataMember]
public int Id { get; set; }
#region Order Details
[DataMember]
public int? ReferenceNumber { get; set; }
[DataMember]
public virtual Status CurrentStatus { get; set; }
[DataMember]
public DateTime? CurrentStatusUpdatedOn { get; set; }
[DataMember]
[MaxLength(1024)] public string ArchiveFileName { get; set; }
[DataMember]
public double TotalPrice { get; set; }
[DataMember]
public bool DigitallySigned { get; set; }
[DataMember]
public int DigitalSigningReferenceId { get; set; }
[DataMember]
public virtual Priority Priority { get; set; }
[DataMember]
public virtual ICollection<Item> Items { get; set; }
.....
}
[DataContract]
public class Item : IItem
{
[DataMember]
[Key]
public int Id { get; set; }
[DataMember]
public virtual Order ParentOrder { get; set; }
[DataMember]
public virtual ItemType Type { get; set; }
[DataMember]
public string ItemReference { get; set; }
[DataMember]
public int FeeReference { get; set; }
[DataMember]
public int Quantity { get; set; }
[DataMember]
public decimal Price { get; set; }
[DataMember]
public string Name { get; set; }
....
}
private static bool UpdateOrderDetails(Order order, DatabaseContext context)
{
var savedOrder =
context.Orders.Include("Priority").Include("CurrentStatus").Where(o => o.Id == order.Id).FirstOrDefault();
//context.Orders.SingleOrDefault(o => o.Id == order.Id);
if (savedOrder != null)
{
savedOrder.Priority = order.Priority;
savedOrder.ReferenceNumber = order.ReferenceNumber;
savedOrder.ShohamId = order.ShohamId;
savedOrder.TotalPrice = order.TotalPrice;
savedOrder.UpdatedOn = DateTime.Now;
savedOrder.CreatedOn = order.CreatedOn;
savedOrder.ArchiveFileName = order.ArchiveFileName;
savedOrder.ClientEmail = order.ClientEmail;
savedOrder.ClientFirstName = order.ClientFirstName;
savedOrder.ClientIdentificationNumber = order.ClientIdentificationNumber;
savedOrder.ClientIdentificationType = order.ClientIdentificationType;
savedOrder.ClientLastName = order.ClientLastName;
savedOrder.ClientPrimaryPhone = order.ClientPrimaryPhone;
savedOrder.ClientSecondaryPhone = order.ClientSecondaryPhone;
savedOrder.CurrentStatus = order.CurrentStatus;
savedOrder.CurrentStatusUpdatedOn = order.CurrentStatusUpdatedOn;
savedOrder.DigitallySigned = order.DigitallySigned;
savedOrder.DigitalSigningReferenceId = order.DigitalSigningReferenceId;
if (order.Items != null)
{
foreach (var item in order.Items)
{
var savedItem = savedOrder.Items.Single(x => x.ItemReference == item.ItemReference);
if (savedItem != null)
{
savedItem.Price = item.Price;
savedItem.Quantity = item.Quantity;
}
}
}
context.Entry(savedOrder).State = EntityState.Modified;
var i = context.SaveChanges();

Answer 1

If you don't want to insert new objects for your navigation properties you must attach them to the context before you assign the values. For your items collection problem you need to include the collection when you query. Including the other two navigation properties is not necessary and setting the state to Modified manually neither in your example. For Include you can use a strongly typed version in EF 4.1 with a lambda expression:
private static bool UpdateOrderDetails(Order order, DatabaseContext context)
{
var savedOrder = context.Orders.Include(o => o.Items)
.Where(o => o.Id == order.Id)
.FirstOrDefault();
if (savedOrder != null)
{
context.Priorities.Attach(order.Priority);
context.CurrentStati.Attach(order.CurrentStatus);
savedOrder.Priority = order.Priority;
// etc.
var i = context.SaveChanges();
}
}