Thanks for such a great article .I am using visual studio 2010 with oracle and nhibernate 2.0 .The same thing started to happen while I was implementing. Then I found out you’re blog , the problem is that I did everything as you mentioned , step by step.My WCF service calls the methods and gives me back the data , but I don’t know that as soon as the WCF call end and the call comes back to the proxy at my client , it doesn’t returns anything …I tried many things but it didn’t worked .
At my Client :
//My Proxy
CustomerServiceClient cl = new CustomerServiceClient();
//Opening the proxy
cl.Open();
//Calling the Method via WCF service which is decorated by
// UseNetDataContractSerializer and I didnt used DataContract and
//DataMemeber for my entity i simply used Serializable attribute.

object[] cust = cl.GetCustomersWithTheirOrders();

Now the GetCustomersWithTheirOrders() is working perfectly fine and bringing the collection
untill it is at the service layer.But when it crosses the service layer and comes to my WebApplication , it is not returning anything , instead it shows empty colection.

I am not getting why is the data being missed while it is fully populated at the WCF service layer.Is it some kind of deserialization problem ? although i used youre implementation as you had mentioned.

I am desperately waiting for you’re or anyone’s reply regarding this query.

bcz i was afraid to use nhibernate with wcf before reading this article.
after reading this article it worked perfect for me.

now it is so easy to transfer nhibernate entities over wcf wire to client.

Thank you once again.

Datta

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 a lot !

Anyway I wanted to know how you manage to persist your DTO’s to the database with NH ? I want to do the following :

Load business model entity with NHibernate
Convert business model entity to dto (by just keeping the properties I need)
Client modifies dto and send it back to the server
Server convert dto back to business model entity
NH persists business model entity to database.

But there’s a problem : Since the dto is a smaller version of the business model entity, that means when I re-create my entity on the server side, it’s not going to be a full-feature entity, so how NHibernate is going to figure out what to save ? It’s probably going to interpret that as many properties have changed (when in fact they haven’t) and persists wrong data in the DB.

You insight would be appreciated.

i got the same exception sometimes, but i think i only got it when i was hosting the service both through IIS and the Console host… not sure though

either way, this entire approach of sending detached NHibernate entities over WCF is something i no longer recommend… i prefer to keep my NHibernate entities inside the service layer, and send specific DTO’s over WCF

the exception occurs when calling

IList customers = proxy.GetCustomersWithTheirOrders();

I debug insîde the Service and it read the information right. ( 1 Order with 2 Lines )

The exception type is System.ArgumentException

The stack Trace is as follows

“\r\nServer stack trace: \r\n at System.RuntimeType.CheckValue(Object value, Binder binder, CultureInfo culture, BindingFlags invokeAttr)\r\n at System.Reflection.RtFieldInfo.InternalSetValue(Object obj, Object value, BindingFlags invokeAttr, Binder binder, CultureInfo culture, Boolean doVisibilityCheck, Boolean doCheckConsistency)\r\n at System.Reflection.RtFieldInfo.InternalSetValue(Object obj, Object value, BindingFlags invokeAttr, Binder binder, CultureInfo culture, Boolean doVisibilityCheck)\r\n at System.Runtime.Serialization.FormatterServices.SerializationSetValue(MemberInfo fi, Object target, Object value)\r\n at System.Runtime.Serialization.FormatterServices.PopulateObjectMembers(Object obj, MemberInfo[] members, Object[] data)\r\n at Castle.DynamicProxy.Serialization.ProxyObjectReference.RecreateClassProxy(SerializationInfo info, StreamingContext context)\r\n at Castle.DynamicProxy.Serialization.ProxyObjectReference.RecreateProxy(SerializationInfo info, StreamingContext context)\r\n at Castle.DynamicProxy.Serialization.ProxyObjectReference..ctor(SerializationInfo info, StreamingContext context)\r\n at ReadProxyObjectReferenceFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadOrderFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadArrayOfanyTypeFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString , XmlDictionaryString , CollectionDataContract )\r\n at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadSerializationInfo(XmlReaderDelegator xmlReader, Type type)\r\n at ReadArrayOfKeyValueOfanyTypeanyTypeFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadCollectionEntryFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadPersistentGenericSetOfOrderSwFpc1QfFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadCustomerFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadArrayOfCustomerFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString , XmlDictionaryString , CollectionDataContract )\r\n at System.Runtime.Serialization.CollectionDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle, String name, String ns)\r\n at ReadArrayOfCustomerFromXml(XmlReaderDelegator , XmlObjectSerializerReadContext , XmlDictionaryString[] , XmlDictionaryString[] )\r\n at System.Runtime.Serialization.ClassDataContract.ReadXmlValue(XmlReaderDelegator xmlReader, XmlObjectSerializerReadContext context)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContext.ReadDataContractValue(DataContract dataContract, XmlReaderDelegator reader)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserializeInSharedTypeMode(XmlReaderDelegator xmlReader, Int32 declaredTypeID, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.XmlObjectSerializerReadContextComplex.InternalDeserialize(XmlReaderDelegator xmlReader, Type declaredType, String name, String ns)\r\n at System.Runtime.Serialization.NetDataContractSerializer.InternalReadObject(XmlReaderDelegator xmlReader, Boolean verifyObjectName)\r\n at System.Runtime.Serialization.XmlObjectSerializer.ReadObjectHandleExceptions(XmlReaderDelegator reader, Boolean verifyObjectName)\r\n at System.Runtime.Serialization.NetDataContractSerializer.ReadObject(XmlDictionaryReader reader, Boolean verifyObjectName)\r\n at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameterPart(XmlDictionaryReader reader, PartInfo part, Boolean isRequest)\r\n at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeParameter(XmlDictionaryReader reader, PartInfo part, Boolean isRequest)\r\n at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.DeserializeBody(XmlDictionaryReader reader, MessageVersion version, String action, MessageDescription messageDescription, Object[] parameters, Boolean isRequest)\r\n at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeBodyContents(Message message, Object[] parameters, Boolean isRequest)\r\n at System.ServiceModel.Dispatcher.OperationFormatter.DeserializeReply(Message message, Object[] parameters)\r\n at System.ServiceModel.Dispatcher.ProxyOperationRuntime.AfterReply(ProxyRpc& rpc)\r\n at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)\r\n at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)\r\n at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs)\r\n at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)\r\n at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)\r\n\r\nException rethrown at [0]: \r\n at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)\r\n at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)\r\n at ServiceInterface.ICustomerService.GetCustomersWithTheirOrders()\r\n at ServiceClient.Program.Main(String[] args) in C:\\Projects\\NHibernate\\WCF\\NhibernateAndWcf\\ServiceClient\\Program.cs:line 16\r\n at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)\r\n at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)\r\n at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()\r\n at System.Threading.ThreadHelper.ThreadStart_Context(Object state)\r\n at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)\r\n at System.Threading.ThreadHelper.ThreadStart()”

I dowloaded the sample and compiled it.

The domain and nHibernate sections work, but when running the WCF client ( Web or Console ) I get the following Exception

{“Object of type ‘Iesi.Collections.Generic.HashedSet`1[Northwind.Domain.Entities.Employee]‘ cannot be converted to type ‘Iesi.Collections.Generic.ISet`1[Northwind.Domain.Entities.Order]‘.”}

Like it is trying to assign an employee object to an Order.

what can be going wrong ?

Thanks anyway

like i said, the only thing i can think of is code in your objects that’s triggered during the deserialization which accesses the proxies. If that’s not it, i can’t help you i guess…

When I use the sample from MSDN with IExtensibleDataObject i cannot serialize and get an error that the nHibernate proxies do not implement IExtensibleDataObject.

When I use NetDataContractSerializer as is without adding anything (except [Serializable]) then it is serializes but I get the session error when deserialize.

the only thing that worked was DataContractSerializer but then Ilist was deserialized as arrays.

So I am quite lost. I don’t know what to do to get it to work….I am actually thinking of using Linq cos I cannot make the nHibernate to work along with serialization…

Any ideas? The IDataContractSurrogate made DataContractSerializer work… Is there anything simlilar for NetDataContractSerializer?

Are you accessing any proxied objects or proxied collections within your object in code that could be touched during deserialization? Depending on how the NetDataContractSerializer sets the data (through setters for instance), it could trigger code that would access contained proxies which could cause that exception.

Yes.. I am only trying to serialize and deserialize objects but nHibernate keeps messing things.

Now i only have [Serializable] attributes on the classes (no DataContract, DataMember, UseNetDataContractSerializer) and I am still getting the following error when I deserialize:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> NHibernate.LazyInitializationException: Could not initialize proxy – no Session..

Also i am not that sure that the object is serialized correctly as when I look at the xml it does not contain a value of a string property the object instance had.

BTW – when I tried to follow the example from msdn using IExtensibleDataObject I got an error that the nHibernate proxies do not implement IExtensibleDataObject.

Do you have any idea how I can simply serialize/deserialize without nHibernate messing everything (and with IList deserialized into Ilist and not arrays).

Many thanks!!

N

The [UseNetDataContractSerializer] is a custom attribute which modifies the behavior of a WCF OperationDescription. If you’re not using WCF, simply putting this attribute on your getters isn’t going to make a difference. Unless you modified the code of the attribute to do something completely different.

If you want to use the NetDataContractSerializer directly to serialize/deserialize your classes, you don’t need to use any attributes on the members of your classes. Just tag the classes themselves with [Serializable] and use the NetDataContractSerializer like you would normally use the XmlSerializer.

You can find more information on the NetDataContractSerializer here:
http://msdn.microsoft.com/en-us/library/system.runtime.serialization.netdatacontractserializer.aspx

I need to serialize / deserialize object to cml and since I am using nHibernate I have to use NetDataContractSerializer/DataContractSerializer.

I used the above code and put [UseNetDataContractSerializer] on the getters of the IList (which so far failed to serialize or deserialized as array when using UseNetDataContractSerializer. The serialize works OK now but when I deserialize I get the following exception:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> NHibernate.LazyInitializationException: Could not initialize proxy – no Session..

Any ideas? Not Really sure what to do.

Thanks
N

the compact framework isn’t listed among the supported .NET frameworks