WCF + EF return object with FK - entity-framework

Question

I am facing following issue: I have ProductOrder class which has ProductId as foreign key to Product class. When I invoke following method:
public IEnumerable<ProductOrder> GetOrders()
{
return OddzialDb.ProductOrders;
}
Orders are associated with Product so I can write something like this:
OddzialDb.ProductOrders.First().Product.Name;
but when it reaches Client it turns out that there is no association with Product which is null (only ProductId is included). In DbContext I have set
base.Configuration.ProxyCreationEnabled = false;
base.Configuration.LazyLoadingEnabled = false;
On the WCF Service side auto-generated by EF ProductOrder class looks as follows:
public partial class ProductOrder
{
public int Id { get; set; }
public Nullable<int> ProductId { get; set; }
public int Quantity { get; set; }
public virtual Product Product { get; set; }
}
What happens that it looses connections with tables associated by foreign keys?

Answer 1

Make your relationship virtual as in the example:
public class ProductOrder
{
public int Id { get; set; }
public virtual Product Product { get; set; }
public int ProductId { get; set; }
}
By turning your relationship virtual, the Entity Framework will generate a proxy of your ProductOrder class that will contain a reference of the Product.
To make sure it will work, Product also has to contain reference to ProductOrder:
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<ProductOrder> ProductOrders { get; set; }
}
Set these variables true on your DbContext:
Configuration.LazyLoadingEnabled = true;
Configuration.ProxyCreationEnabled = true;
On your WCF application, add the following class, which will allow for proxy serialization:
public class ApplyDataContractResolverAttribute : Attribute, IOperationBehavior
{
public ApplyDataContractResolverAttribute()
{
}
public void AddBindingParameters(OperationDescription description, BindingParameterCollection parameters)
{
}
public void ApplyClientBehavior(OperationDescription description, System.ServiceModel.Dispatcher.ClientOperation proxy)
{
DataContractSerializerOperationBehavior dataContractSerializerOperationBehavior =
description.Behaviors.Find<DataContractSerializerOperationBehavior>();
dataContractSerializerOperationBehavior.DataContractResolver =
new ProxyDataContractResolver();
}
public void ApplyDispatchBehavior(OperationDescription description, System.ServiceModel.Dispatcher.DispatchOperation dispatch)
{
DataContractSerializerOperationBehavior dataContractSerializerOperationBehavior =
description.Behaviors.Find<DataContractSerializerOperationBehavior>();
dataContractSerializerOperationBehavior.DataContractResolver =
new ProxyDataContractResolver();
}
public void Validate(OperationDescription description)
{
// Do validation.
}
}
Then on your ServiceContract interfaces you add the DataAnnotation [ApplyDataContractResolver] right among your other annotations such as [OperationContract], above any method signature that returns an entity:
[OperationContract]
[ApplyDataContractResolver]
[FaultContract(typeof(AtcWcfEntryNotFoundException))]
Case GetSingleByCaseNumber(int number);