ObjectNetworkAttacher vs. DataContractSerializer

[NemFontos]

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?

[NemFontos]

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.)

[NemFontos]

Aha!

If I'm getting the value of .Version explicitly (i.e. int v = object.Version) then the value of this property stay there. If I'm only run the serializer on this object - the real value is missing! (I'm getting just default 0)

The question: how is possible toforce to fill the Version property? Some VEnhance trick?

[Jan Blessenohl]

Hi NemFontos,
In the forward mapping wizard you can choose your new field as version field by selection the class in the tree.

You can also modify the persistent attribute by hand

[Telerik.OpenAccess.Persistent(VersionField="v"]

Regards,
Jan Blessenohl
the Telerik team

Check out Telerik Trainer , the state of the art learning tool for Telerik products.

[NemFontos]

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

[Jan Blessenohl]

Hi NemFontos,
Before you pass the object to the serializer you should call objectscope.Retrieve() on that object. This will load all values to the object.

All the best,
Jan Blessenohl
the Telerik team

Check out Telerik Trainer , the state of the art learning tool for Telerik products.

[NemFontos]

Great, thank you!