Automapper mapping type with subtype

Question

I've got a case in which I need to map something like this:

public class Event
{
    string Name {get;set;}
    int EventType {get;set;}
    SubType Sub {get;set;}
}

The problem is that the way SubType inside should be mapped is determined by the EventType property of the Event class. For different types of events I want different things to be mapped.

The usual way is to create maps for both Event and SubType - they are not related to each other:

 map.CreateMap<EventDTO, Event>();
 map.CreateMap<SubTypeDTO, SubType>();

How can I tell automapper to change behaviour in the SubType mapping based on the Event.EventType?

PS> I know this is bad design and it really should be resolved by refactoring the whole thing ( eg. removing the EventType and creating subclasses ) Unfortunately I inherited this code and just need to resolve bugs without spending to much time.

Answer 1

I'm not sure if there's something to achieve this, but you could do the following:

 Mapper.CreateMap<EventDTO, Event>()
            .ForMember(to => to.Name, from => from.Ignore() )
            .ForMember(to => to.Sub, from => from.Ignore() )
            .ForMember(to => to.EventType, from => from.Ignore() )
            .AfterMap((source, dest) =>
                          {
                              switch (dest.EventType)
                              {
                                  case 1:
                                      // Behaviour EventType 1
                                      ...
                                      dest.Name = source.NameDTO + "1";
                                      ...
                                      break;
                                  case 2:
                                      // Behaviour EventType 2
                                      ...
                                      dest.Name = source.NameDTO + "2";
                                      ...
                                      break;
                                  default:
                                      // Behaviour EventType 3
                                      ...
                                      dest.Name = source.NameDTO + "0";
                                      ...
                                      break;
                              }
                          });