WCF with abstract base class with implemented interfaces does not serialize properly? - wcf

Question

On the service side I have an abstract base class like so:
[DataContract]
public abstract class EntityBase : IObjectState, IDatabaseMetaData
{
[NotMapped]
[DataMember]
public ObjectState ObjectState { get; set; }
#region IDatabaseMetaData Members
[DataMember] public DateTime InsertDatetime { get; set; }
[DataMember] public int InsertSystemUserId { get; set; }
[DataMember] public DateTime? UpdateDatetime { get; set; }
[DataMember] public int? UpdateSystemUserId { get; set; }
public virtual SystemUser InsertSystemUser { get; set; }
public virtual SystemUser UpdateSystemUser { get; set; }
#endregion
}
Here is an implementing class (data contract):
[DataContract(Namespace = Constants.MyNamespace)]
public class AccountClass : EntityBase
{
[DataMember] public int AccountClassId { get; set; }
[DataMember] public string AccountClassCode { get; set; }
[DataMember] public string AccountClassDesc { get; set; }
}
On the client side I have essentially duplicated contracts. Here is the Client.AccountClass:
public class AccountClass : ObjectBase
{
private int _accountClassId;
private string _accountClassCode;
private string _accountClassDesc;
public int AccountClassId
{
get { return _accountClassId;}
set
{
if (_accountClassId == value) return;
_accountClassId = value;
OnPropertyChanged(() => AccountClassId);
}
}
public string AccountClassCode
{
get { return _accountClassCode; }
set
{
if (_accountClassCode == value) return;
_accountClassCode = value;
OnPropertyChanged(() => AccountClassCode);
}
}
public string AccountClassDesc
{
get { return _accountClassDesc; }
set
{
if (_accountClassDesc == value) return;
_accountClassDesc = value;
OnPropertyChanged(() => AccountClassDesc);
}
}
}
..and here is the parts of ObjectBase that matter:
public abstract class ObjectBase : IObjectState, IDatabaseMetaData
{
public ObjectState ObjectState { get; set; }
#region IDatabaseMetaData Members
public DateTime InsertDatetime { get; set; }
public int InsertSystemUserId { get; set; }
public DateTime? UpdateDatetime { get; set; }
public int? UpdateSystemUserId { get; set; }
#endregion
}
When I debug the service in my WcfMessageInspector.BeforeSendReply, I can see the message correctly sending the IObjectState and IDatabaseMetaData values. However, on the client side, they are always null (or default values). I have tried using KnownTypes, applying the namespace to the abstract class. The only way I can serialize everything correctly is to get rid of the interfaces and base classes all together and put the properties directly on the Client/Server AccountClass object. What am I missing here? Thanks.
Update 1
This seems to be a namespace thing. If I move my EntityBase and ObjectBase into the same CLR Namespace, everything works (with no KnownType attributes). In my client contract's AssemblyInfo.cs file I have this:
[assembly: ContractNamespace(Constants.MyNamespace, ClrNamespace = "Project.Name.Client.Entities")]
I tried adding ContractNamespaces here to no avail. Like I said, unless the EntityBase and ObjectBase are in the same namespace, it won't work. However, this is a problem for me because it creates a circular reference, unless I move a lot of stuff around.
Any idea how I can see what the full data contract (namespaces, DataMembers, etc) looks like just before/after serialization on the client/server? I tried intercepting the OnSerializing event without much luck. Thanks again.

Answer 1

This was a namespace issue.
I explicitly add the correct namespace to all parties involved and everything works great. One thing I notice is that the ContractNamespace's ClrNamespace in your AssemblyInfo.cs file should match the AssemblyTitle. Also, putting more than one ContractNamespace in the AssemblyInfo.cs does nothing. For example, I was doing this:
[assembly: ContractNamespace(Constants.MyNamespace, ClrNamespace = "Company.Project.Client.Entities")]
[assembly: ContractNamespace(Constants.MyNamespace, ClrNamespace = "Company.Project.Client.Entities.Core")]
Any POCO in the Company.Project.Client.Entities.Core would not serialize correctly until I explicitly put the DataContract namespace on it like so
[DataContract(Namespace = Constants.MyNamespace)]
public class SomeObject
{
[DataMember] public string SomeProperty { get; set; }
//..etc
}
Alternatively, I could have restructured the project so SomeObject was in the Company.Project.Client.Entities namespace and that would have worked.
Finally, the most helpful thing to debugging this was looking at the WSDL, and then using a custom IDispatchMessageInspector to see the actual messages AfterReceiveRequest and BeforeSendReply. Hopefully this helps someone.