Exchanging data between classes - DI, IoC

Question

My setup is:

class ModelA { ... }
interface IModelARetriever {  IEnumerable<ModelA> GetObjects(); }

class ModelB { ... }
class DomainObject { List<ModelB> ModelBList; }

DomainObject.ModelBList could be appended using manipulated data from lists of ModelA objects, but not neccessarily. Where should I put the logic for this?

Should I create a method in DomainObject that takes a IEnumerable<ModelA> ? That would mean changing the DomainObject for every possible source of data that can create objects of ModelB.

Should I create a separate interface ModelBFactory and extend that? This sounds best, but just want an expert opinion.

Answer 1

If I've read the question correctly, ModelA objects can be converted into ModelB objects. I'd say that calls for a ToModelB() method on ModelA . If the conversion is straightforward (say, just copying a subset of ModelA 's property values), I'd implement it in ToModelB() directly; if it's more complex (say, conditional copying of some property values, combination of values, arithmetic, etc) I'd have a ModelAConverter class which did the job.

I'd then add the AddModelAObjects() method you mentioned to DomainObject . You then have two choices of how you convert the ModelA s into ModelB s - you either have the ModelAConverter injected into DomainObject 's constructor and do the conversion in AddModelAObjects() , or into ModelA 's constructor and do the conversion in ToModelB() . I'd probably go with the latter, but it depends on what else the objects have to do.