When using a proxy generated by svcutils ?

I’ve tried to use a code to replace the behaviour in the client – but it doesn’t work (the deserializer looking from staff in the wrong places… – looking for on of my server entities in mscorlib) :
foreach (OperationDescription desc in this.Endpoint.Contract.Operations)
{
DataContractSerializerOperationBehavior dcsOperationBehavior = desc.Behaviors.Find();
if (dcsOperationBehavior != null)
{
int idx = desc.Behaviors.IndexOf(dcsOperationBehavior);
desc.Behaviors.Remove(dcsOperationBehavior);
desc.Behaviors.Insert(idx, new NetDataContractOperationBehavior(desc));

}
}

I am trying to access the WCF service having following interface and implementation:

[ServiceContract(Namespace="http://SMS.com/OPS")]
public interface IOrderProcessingService
{
   [UseNetDataContractSerializer]
   [OperationContract]
   Customer GetAnyCustomer();

   [UseNetDataContractSerializer]
   [OperationContract]
   Customer GetCustomerByName(string customerName);
}

public class OrderProcessingService : IOrderProcessingService
{
   public Customer GetAnyCustomer()
   {
      ICustomerRepository repository = new CustomerRepository();
      return repository.GetByName(“Tom”);
   }

   public Customer GetCustomerByName(string customerName)
   {
      ICustomerRepository repository = new CustomerRepository();
      return repository.GetByName(customerName);
   }
}

CustomerRepository class is accessing the database using NHibernate.

Now the problem is that the method GetAnyCustomer() is working fine. But when the service client is accessing the method GetCustomerByName, the following exception is thrown, indicating that there is some problem in deserializing the given string parameter customerName. The exception details are as follows:
WorkingWithGraph.Tests.OrderProcessingServiceTest.GetCustomerByNameTest : System.ServiceModel.FaultException : The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter http://SMS.com/OPS:customerName. The InnerException message was ‘Error in line 1 position 281. XML ‘Element’ ‘http://SMS.com/OPS:customerName’ does not contain expected attribute ‘http://schemas.microsoft.com/2003/10/Serialization/:Type’. The deserializer has no knowledge of which type to deserialize. Check that the type being serialized has the same contract as the type being deserialized.’. Please see InnerException for more details.

And what does it meant by : XML ‘Element’ ‘http://SMS.com/OPS:customerName’ does not contain expected attribute ‘http://schemas.microsoft.com/2003/10/Serialization/:Type’

I have also tried encapsulating the customerName both in a DataContract and in a MessageContract and used these contracts as parameter types, but not to avail anything.

Please help me.

Thanks in advance.
Gaurav

Thanks for the post, I’ve run into the same issue.

What did you do on the client side to specify that you are using the NetDataContractSerializer ?

If I don’t do anything the client throws the following exception :

The deserializer has no knowledge of which type to deserialize. Check that the type being serialized has the same contract as the type being deserialized

More detailed :
The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter http://tempuri.org/:pPostId. The InnerException message was ‘Error in line 1 position 123. XML ‘Element’ ‘http://tempuri.org/:pPostId’ does not contain expected attribute ‘http://schemas.microsoft.com/2003/10/Serialization/:Type’. The deserializer has no knowledge of which type to deserialize. Check that the type being serialized has the same contract as the type being deserialized.’.

However, right now, I’m facing another problem for which I’ve found no solution yet. As I see that a lot of people who have posted comments here which are using NHibernate in a remote scenario plz allow me to do so .

What I want to try to accomplish is -just as Tim Scott & Greg Banister did-, share my business objects on the client and on my remote service layer.
This means that my ‘Customer entity’ for example is known by the client, and is known by the Service Layer.
The problem that I am facing, is state tracking … Let me explain:
Suppose I’ve a method in my remote service which allows me to get a Customer object.
In my client app, I would call it like this:

Customer c = RemoteProxy.GetCustomer (1);

Then, as soon as I’ve retrieved the Customer, the user could make some changes to this Customer object. Or, he could also choose not to change properties on the object.
Anyway, when the user click’s OK, I need to be able to determine if the user has changed, so that I do not unnecessarily invoke the remote call to save the changes.
Then, in my remote interface, I also need to determine whether the object has really changed, so that no unnecessary UPDATE’s are invoked in the DB. (This is also necessary since, when using an Interceptor which sets some audit-information (last updated date, last updated by …), we should have no wrong information in the DB).

I’ve written a post about it on my weblog. Any idea’s of how to solve this problem, is very much appreciated.
http://fgheysels.blogspot.com/2008/07/nhibernate-in-remoting-wcf-scenario.html

How did you guys cope with this problem ?

Heres my code,
[Serializable]
[DataContract]
[KnownType(typeof(NHibernate.Collection.Generic.PersistentGenericSet))]
[KnownType(typeof(Iesi.Collections.Generic.HashedSet))]

[KnownType(typeof(ItemHierarchyLevel))]
[KnownType(typeof(Item))]
public class ItemHierarchy:IItemHierarchy
{
[DataMember]
public virtual Guid Id { get; set; }
[DataMember]
public virtual string Name { get; set; }

public virtual ItemHierarchy Parent { get; set; }
[DataMember]
public virtual ISet Children { get; set; }
[DataMember]
public virtual ItemHierarchyLevel HLevel { get; set; }
[DataMember]
public virtual Item ItemNumber { get; set; }
[DataMember]
public virtual ISet ItemBaseProps { get; set; }
public ItemHierarchy()
{
Children = new HashedSet();
ItemBaseProps = new HashedSet();
//ItemNumber = new Item();
}

public virtual void AddChildItemHierarchy(ItemHierarchy child)
{
Children.Add(child);
child.Parent = this;
}

public virtual void GetObjectData(SerializationInfo info, StreamingContext context)
{
}
}
And this test is ok, with the count of children being correct…

[Test]
public void NetDataContractSerialization_will_Not_change_the_type_of_a_Collection()
{
ItemHierarchy ith = _repository.GetAggregateByName(“Top”);
Assert.AreEqual(typeof(NHibernate.Collection.Generic.PersistentGenericSet), ith.ItemBaseProps.GetType());

NetDataContractSerializer serializer = new NetDataContractSerializer();

//serialize company to a memmory stream
Stream stream = new MemoryStream();
serializer.Serialize(stream, ith);

//deserialize the memory stream back to a company
stream.Position = 0;
ith = (ItemHierarchy)serializer.Deserialize(stream);

Assert.AreEqual(typeof(NHibernate.Collection.Generic.PersistentGenericSet), ith.ItemBaseProps.GetType());
Assert.AreNotEqual(typeof(object[]), ith.ItemBaseProps.GetType());
}

Any ideas welcomed,

Maybe I will write an article about this a bit later.

I am serializing by hand so I don’t know how it would work with WCF, but I am sure there has to be a way to set a surrogate when serializing.

I am going to post on it soon, but if you want to check it out just email me.