InvalidDataContractException ("Type cannot be serialized") error using WCF DataContract

Question

I need to pass System.Net.NetworkInformation.PhysicalAddress (.NET Framework built-in type) in my data contract. Since this type cannot be serialized by itself, I derived my helper class from it:

[DataContract]
public class PhysicalAddressSerializable : PhysicalAddress
{
    public PhysicalAddressSerializable()
        : base(new byte[] {0,0,0,0,0,0})
    { }
    public PhysicalAddressSerializable(byte[] address) 
        : base(address)
    { }

    [DataMember]
    public string AddressString { get { return ToString(); } set { Parse(value); } }
}

It serializes to XML pefectly; however, when I try to pass it into service call, I'm getting System.Runtime.Serialization.InvalidDataContractException:

Type 'System.Net.NetworkInformation.PhysicalAddress' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. If the type is a collection, consider marking it with the CollectionDataContractAttribute. See the Microsoft .NET Framework documentation for other supported types.

Stack trace:

Server stack trace: 
   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.ThrowInvalidDataContractException(String message, Type type)
   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.CreateDataContract(Int32 id, RuntimeTypeHandle typeHandle, Type type)
   at System.Runtime.Serialization.DataContract.GetDataContract(Int32 id, RuntimeTypeHandle typeHandle, SerializationMode mode)
   at System.Runtime.Serialization.ClassDataContract.ClassDataContractCriticalHelper..ctor(Type type)
   at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.CreateDataContract(Int32 id, RuntimeTypeHandle typeHandle, Type type)
   at System.Runtime.Serialization.DataContract.GetDataContract(Int32 id, RuntimeTypeHandle typeHandle, SerializationMode mode)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerialize(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.InternalSerializeReference(XmlWriterDelegator xmlWriter, Object obj, Boolean isDeclaredType, Boolean writeXsiType, Int32 declaredTypeID, RuntimeTypeHandle declaredTypeHandle)
   at WriteUnitInfoToXml(XmlWriterDelegator , Object , XmlObjectSerializerWriteContext , ClassDataContract )
   at System.Runtime.Serialization.ClassDataContract.WriteXmlValue(XmlWriterDelegator xmlWriter, Object obj, XmlObjectSerializerWriteContext context)
   at System.Runtime.Serialization.XmlObjectSerializerWriteContext.SerializeWithoutXsiType(DataContract dataContract, XmlWriterDelegator xmlWriter, Object obj, RuntimeTypeHandle declaredTypeHandle)
   at System.Runtime.Serialization.DataContractSerializer.InternalWriteObjectContent(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver)
   at System.Runtime.Serialization.DataContractSerializer.InternalWriteObject(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver)
   at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver)
   at System.Runtime.Serialization.XmlObjectSerializer.WriteObject(XmlDictionaryWriter writer, Object graph)
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameterPart(XmlDictionaryWriter writer, PartInfo part, Object graph)
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameter(XmlDictionaryWriter writer, PartInfo part, Object graph)
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeParameters(XmlDictionaryWriter writer, PartInfo[] parts, Object[] parameters)
   at System.ServiceModel.Dispatcher.DataContractSerializerOperationFormatter.SerializeBody(XmlDictionaryWriter writer, MessageVersion version, String action, MessageDescription messageDescription, Object returnValue, Object[] parameters, Boolean isRequest)
   at System.ServiceModel.Dispatcher.OperationFormatter.OperationFormatterMessage.OperationFormatterBodyWriter.OnWriteBodyContents(XmlDictionaryWriter writer)
   at System.ServiceModel.Channels.Message.OnWriteMessage(XmlDictionaryWriter writer)
   at System.ServiceModel.Channels.BufferedMessageWriter.WriteMessage(Message message, BufferManager bufferManager, Int32 initialOffset, Int32 maxSizeQuota)
   at System.ServiceModel.Channels.BinaryMessageEncoderFactory.BinaryMessageEncoder.WriteMessage(Message message, Int32 maxMessageSize, BufferManager bufferManager, Int32 messageOffset)
   at System.ServiceModel.Channels.FramingDuplexSessionChannel.EncodeMessage(Message message)
   at System.ServiceModel.Channels.FramingDuplexSessionChannel.OnSendCore(Message message, TimeSpan timeout)
   at System.ServiceModel.Channels.TransportDuplexSessionChannel.OnSend(Message message, TimeSpan timeout)
   at System.ServiceModel.Channels.OutputChannel.Send(Message message, TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
   at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
   at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]: 
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)

Answer 1

As per the error message, it is unhappy about PhysicalAddress, the base-class. So either:

• don't use the base-class - use a simple DTO that doesn't need it, or:
• mark the base-class for serialization

Specifically, something like:

[DataContract, KnownType(PhysicalAddressSerializable)]
public class PhysicalAddress {
    [DataMember(...)]
    public SomeType Foo {get;set;} // whatever
}

However! From the name PhysicalAddressSerializable, it sounds like you don't want to have the base-class as serializable. You could try using:

[XmlSerializerFormat]
public class PhysicalAddressSerializable : PhysicalAddress {...}