The type xxx was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically

Question

So the old code base was working fine when I could place a message on MSMQ. However the new codebase I received does not work and no idea what I am missing to be honest.

Base class:

    [DataContract]
    [KnownType(typeof (ReportA))]
    [KnownType(typeof (AUpdate))]
    [KnownType(typeof (AStatusReport))]
    [KnownType(typeof (MsgHeader))]
    [KnownType(typeof(BRegistationReport))]
    [KnownType(typeof(BAlarmReport))]
    [KnownType(typeof(AlarmData))]
    [KnownType(typeof(DmpAlarmData))]
    public class MyMessage {....}

Then the specific class here, BAlarmReport (derives from MyMessage):

[DataContract]
public class BAlarmReport: MyMessage 
{ ... }

Then you can have AlarmData as a base which is inherited from DmpAlarmData:

[DataContract]
    public class DmpAlarmData : AlarmData
{ .. }

The way I am placing it on MSMQ is the same as before, which was working until I got the new codebase:

var queue = new MessageQueue(@"FormatName:Direct=OS:" + mMSMQQueueNameAndLocation);
var msg = new Message {Body = MyMessage.CreateMessage() };

using (var ts = new TransactionScope(TransactionScopeOption.Required))
{
    queue.Send(msg, MessageQueueTransactionType.Automatic); // send the message
    ts.Complete(); // complete the transaction
}

am I missing something?

Answer 1

Fixed. sigh

Digging through the inner exceptions led me to the problem where some of the classes did not have a parameterless constructor. But also the subclasses should be declared with the XmlInclude attribute on the base class itself.