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ObjectNetworkAttacher vs. DataContractSerializer

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NemFontos asked on 21 Mar 2009, 08:58 PM

Hi,

I'm writing some proof-of-concept code using ObjectNetworkAttacher and your oneexample.zip.

Instead of XmlSerializer (cause of IList bug) I'm using NetContractSerializer/DataContract serializer. The last one work well: I can deserialize and serialize objects with IList (modified from oneexample.zip):

    
              byte[] serializedObject = null;
 
              using (MemoryStream stream = new MemoryStream())
 
              {
 
              DataContractSerializer serializer = new DataContractSerializer(typeof(B));
 
              serializer.WriteObject(stream, b);
 
              serializedObject = stream.GetBuffer();
 
              }

But.

When I try to commit my changes back to the database

    
                        // deserialize b
 
                        MemoryStream stream2 = new MemoryStream(serializedObject);            
 
                        DataContractSerializer serializer2 = new DataContractSerializer(typeof(B));
 
                        B deserializedB = (B)serializer2.ReadObject(stream2);
 
                        deserializedB.Name = "changed";
 
                        // attach 
 
                        scope = ObjectScopeProvider1.GetNewObjectScope();
 
                        scope.Transaction.Begin();
 
                        B attachedB = (B) ObjectNetworkAttacher.AttachXML(scope, deserializedB);
 
                        scope.Transaction.Commit(); // throws exception

I've got "A conflicting object was added remotely and concurrently in the database." exception. ObjectNetworkAttacher thinks that this object is "remotenew".

I think there is a version member issue, because the version propery is 0 and not 1 - but why?

6 Answers, 1 is accepted

answered on 21 Mar 2009, 09:14 PM

I found an interessing behavior

    
                        scope.Transaction.Begin();
 
                        // serialize a;
 
                        MemoryStream stream = new MemoryStream();
 
                        DataContractSerializer serializer = new DataContractSerializer(typeof(B));
 
                        serializer.WriteObject(stream, b);
 
                        byte[] serializedObject = stream.GetBuffer();
 
                        // log
 
                        using (StreamWriter sw = new StreamWriter("temp.xml"))
 
                        {
 
                            sw.Write(Encoding.ASCII.GetString(serializedObject));
 
                        }
 
                        // now we can forget the scope
 
                        scope.Transaction.Commit();

The version field is sometimes 0, and sometimes 1. (In the previous step I saved the object already.)

answered on 23 Mar 2009, 12:31 PM

Hi Jan,

thank you. Sadly the value of "version" is still 0 when the DataContractSerializer reads it. (If I "cheat" with an explicit read, OA fills it).

Serialized objects:

    
            <B>
 
            <alist>
 
               <A>
 
                 <id>66d4daee-921b-47f7-9d52-ce9c6666ad79</id>
 
                 <name>Jan</name>
 
                 <version>0</version>
 
                 </A>
 
               </alist>
 
               <date>2009-03-22T00:43:07.377</date>
 
               <id>30d89f0f-4727-4239-8053-80e84c85bd72</id>
 
               <name>Bela</name>
 
               <version>0</version>
 
             </B>

But b.Version == 1 is true in runtime (b is instance of B)

Is there any attribute/configuration to turn off the version lazy-loading?

Thank you,

NemFontos

Accepted