.NET (Core and Framework)

<UnicastBusConfig>
 <MessageEndpointMappings>
    <add Messages="xyz.Messages" Endpoint="xyzServerQueue" />
    <add Messages="xyz.Messages.Domain1" Endpoint="xyzServerQueue" />
    <add Messages="xyz.Messages.Domain2" Endpoint="xyzServerQueue" />
  </MessageEndpointMappings>
</UnicastBusConfig>

<UnicastBusConfig>
 <MessageEndpointMappings>
   <add Messages="xyz.Messages" Endpoint="xyzClientQueue" />
   <add Messages="xyz.Messages.Domain1" Endpoint="xyzClientQueue" />
   <add Messages="xyz.Messages.Domain2" Endpoint="xyzClientQueue" />
 </MessageEndpointMappings>
</UnicastBusConfig>

IBus serviceBus = Configure.With()
    .SpringBuilder()
    .XmlSerializer()
    .MsmqTransport()
    .UnicastBus()
    .LoadMessageHandlers()
    .CreateBus()
    .Start();

Message message= new Message();
Bus.Send(message); // works fine, transfers Message type
message = new MessageDerived1();
Bus.Send(message); // works fine, transfers MessageDerived1 type
message = new MessageDerived2();
Bus.Send(message); // works fine, transfers MessageDerived2 type

public class MessageDerived2 : Message
{
  public Message message;
}

MessageDerived2 messageDerived2= new MessageDerived2();
messageDerived2.message = new MessageDerived1();
message = messageDerived2;
Bus.Send(message); // incorrect behaviour, transfers MessageDerived2 correctly, but looses type of  MessageDerived2.Message (it deserializes as Message type, instead of MessageDerived1)

private void BindingSource_PositionChanged(object sender, EventArgs e) {
  BindingSource bs = (BindingSource)sender;
  FileRecord frec = bs.Current as FileRecord;
  if (frec != null) {
    // FormatData may throw an exception
    Detail.Text = this.FormatData(frec.File);
  } else {
    Detail.Clear();
  }
}