AutoMapper - 映射子列表时非常奇怪的行为

Question

This is most certainly a peculiar issue, and after finding nobody out there with the same issue, I hope I can find someone who actually knows what the problem is.

I've got, say:

public class ViewModel
{
     public string TestString { get; set; }
     public ChildObject Child { get; set; }
     public List<Children> Children { get; set; }
}

Now, when I go to mapping my objects in my controller... ie

TestObject testObject = Repository.GetObject() // This is my Entity Framework object (with dynamic proxies attached to it)
Mapper.Map(ViewModel, testObject);

and, my mappings are defined as:

Mapper.CreateMap<ViewModel, TestObjectType>();
Mapper.CreateMap<ViewModelChildView, TestObjectChildType>();

Everything maps fine, so I've got my ViewModel setup properly, and my form. The problem though? That's the interesting part.

ChildObject is, as the my original objects are, a DynamicProxy (Entity Framework). The List<Children> however, gets set to a normal List (even when the original list is a DynamicProxy of List<Children> ).

This, in turn, means Entity Framework can't access this list as it's not bound to the context properly. I've tried all day to find a workaround with no luck. Any ideas out there?

Edit

These are my actual object bindings:

 Mapper.CreateMap<CompanyViewModel, Company>();
 Mapper.CreateMap<CompanyCategoryViewModel, CompanyCategory>(); // I've ever tried removing this line.
 Mapper.CreateMap<List<CompanyCategoryViewModel>, List<CompanyCategory>>();

Controller:

Mapper.Map(companyViewModel, company);

Company object = Dynamic Proxy CompanyCategories list sub object (of Company), maps, but still not a Dynamic Proxy.

Answer 1

You need both the mapping for the Child object type and also for the collection. If you have a List<> you need to specify List<> in your CreateMap (it won't work with IEnumerable

Mapper.CreateMap<ViewModel, TestObjectType>();
Mapper.CreateMap<ViewModelChildView, TestObjectChildType>();
Mapper.CreateMap<List<ViewModelChildView>>, List<TestObjectChildType>>();

Here is a GIST containing my repro code.

To complete the picture I've used the latest pre-realise version of AutoMapper 2.2.1-ci9004.

Answer 2

So basically the only difference i think is how you create the maps.

perhaps next to

   Mapper.CreateMap<ViewModelChildView, TestObjectChildType>();

you should also create a list mapping like

   Mapper.CreateMap<IEnumerable<ViewModelChildView>, IEnumerable<TestObjectChildType>>();