Custom object returning as "empty" from WCF?

Question

For what reason(s) should WCF return me a "empty" instantiated object when it was clearly populated on my WCF service return before it went over the wire?

For instance a simple OperationContract method:

response.Client = new Client();
response.Client.ID = 99;
return response;

returns an "empty" Client object (on the client receiving end) and all fields are either null or zero. However just before the response, if I inspect response.Client.ID it is populated with 99?

Just to make matters worse, I have an error object and I populate as such:

response.Errors.Add(new CodedError(Errors.ErrorCodes.LOGIN_AUTHENTICATION_ERROR));

However I CAN see the Error list on the receiving end with this? :\

Confusingly yours, Graham

Answer 1

Is your object marked as [Serializable] or is it a [DataContract]? You need to mark your object as one or the other.

WCF only knows how to pass primitives or serializable objects across the wire.

Answer 2

Is the client proxy up to date? I've seen it happen when the contract changes and the client is not updated to reflect the change.

Answer 3

If anyone encounters this problem, I have found the fix. Due to business requirements I had marked my custom class with both [Serializable] and [DataContract], this appears to be illegal possibly as of .NET 3.5 SP1?

I have a friend who is sending WCF objects with both these attributes pre .NET 3.5 SP1 and it is working fine. Interesting.

FYI, I simply used [Serializable] only and it is sending through my object graph correctly. I needed this for xml serialization down the track.

This was a painful issue but glad it is now finally functioning....