How do I get AutoMapper to not cache mapped objects?

Question

When AutoMapper encounters an object that\'s already been mapped, it seems to use that object again, instead of trying to re-map it. I believe it does this based on .Equal

Answer 1

I also get the same issue. It doesn't happen when you map the same object twice - it happens when you have a tree heirarcy of objects, and the same value exists in two places of the tree (but with different child values) When mapping the second instance of the item - it uses the child values of the first instance, instead of re-evaluating what the child values should be.

Here is my example:

class Tag { 
  int Id {get; set;}
  string Name {get; set;}
  IEnumerable ChildTags  {get; set;}
}

public void Test()
{
var source =  new List
            {
                new Tag { Id = 1, Name = "Tag 1", ChildTags = new List
                            {
                                new Tag { Id = 2, Name = "Tag 2", ChildTags = new List 
                                            {
                                                new Tag {Id = 3, Name = "Tag 3"},
                                                new Tag {Id = 4, Name = "Tag 4"}
                                            }
                                    }
                            }
                    },
                new Tag { Id = 1, Name = "Tag 1" },
                new Tag {
                        Id = 3, Name = "Tag 3", ChildTags = new List
                            {
                                new Tag {Id = 4, Name = "Tag 4"}
                            }
                    }
            };

Mapper.CreateMap()
    .ForMember(dest => dest.ChildTags,
        opt => opt.MapFrom(src => src.ChildTags));
var result = Mapper.Map, IList>(tags);
}

In the result

• the first instance of Tag 1 (ie source[0]) and all of its children are perfect

• the second instance of Tag 1 (ie source[1]) has all the children of the first instance - it should not have any children

• the second instance of Tag 3 (ie source[2]) does not have any children - it should have Tag 4 as a child