Deep level mapping using Automapper

Question

I am trying to map objects with multi-level members: these are the classes:

 public class Father
    {
        public int Id { get; set; }
        public Son Son { get; set; }
    }

    public class FatherModel
    {
        public int Id { get; set; }
        public int SonId { get; set; }
    }

    public class Son
    {
        public  int Id { get; set; }
    }

This is how I try automap it:

 AutoMapper.Mapper.CreateMap<FatherModel , Father>()
                      .ForMember(dest => dest.Son.Id, opt => opt.MapFrom(src => src.SonId));

this is the exception that I get:

Expression 'dest => Convert(dest.Son.Id)' must resolve to top-level member and not any child object's properties. Use a custom resolver on the child type or the AfterMap option instead. Parameter name: lambdaExpression

Thanks

To map nested properties with the latest AutoMapper, just use ForPath, instead of ForMember. It works like a charm. — Ε Г И І И О, Aug 31 '22 at 17:19

score 47 · Accepted Answer · answered Mar 21 '13 at 19:11

47

This will work both for mapping to a new or to an existing object.

Mapper.CreateMap<FatherModel, Father>()
    .ForMember(x => x.Son, opt => opt.MapFrom(model => model));
Mapper.CreateMap<FatherModel, Son>()
    .ForMember(x => x.Id, opt => opt.MapFrom(model => model.SonId));

answered Mar 21 '13 at 19:11

Allrameest

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7

The important part of this answer is the mapping of the Son property to the model, that is what forces the use of the second mapping (line 2). – Steve Jan 26 '15 at 10:54

score 21 · Answer 2 · edited Jul 11 '22 at 01:34

21

    AutoMapper.Mapper.CreateMap<FatherModel, Father>()
                     .ForMember(x => x.Son, opt => opt.ResolveUsing(model => new Son() {Id = model.SonId}));

if it's getting more complex you can write a ValueResolver class, see example here- https://docs.automapper.org/en/stable/Custom-value-resolvers.html

edited Jul 11 '22 at 01:34

DeanOC

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answered Mar 21 '13 at 18:56

Maxim

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score 13 · Answer 3 · answered Jan 25 '19 at 16:54

13

Use ForPath rather than ForMember & It works like magic.

answered Jan 25 '19 at 16:54

Teja Swaroop

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Answers suggesting ```.MapFrom()``` didn't work for me, but this did. – derekbaker783 Nov 17 '20 at 20:15

score 0 · Answer 4 · answered Jul 16 '23 at 10:02

0

AutoMapper.Mapper.CreateMap<FatherModel ,Father>()
         .ForMember(dest => dest.Son, opt => opt.MapFrom(src => new Son {Id = src.SonId}));

it Works correctly

answered Jul 16 '23 at 10:02

mojtaba nazarzadeh

1
1

As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jul 19 '23 at 00:33

Deep level mapping using Automapper

4 Answers4

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