Difference between revisions of "AutoMapper"

Latest revision as of 10:47, 17 March 2026

Installation

Command line

dotnet add package AutoMapper

PM>

Install-Package AutoMapper

Creating Profile

This is a complex tree model structure To create parent children mapping, create the child mapping first and then create parent children mapping. CreateMap<Source, Target>

  public class ApplicationProfile:AutoMapper.Profile
    {
        public ApplicationProfile()
        {
            CreateMap<Common.Models.Entities.VDS.Proposal, ProposalForm>();
            CreateMap<Common.Models.Entities.VDS.Section, Models.Insurance.Section>();
            CreateMap<Common.Models.Entities.VDS.ProposalQuestionAnswer, ProposalFormQuestionAnswer>()
                .ForMember(dest => dest.ProposalFormQuestionAnswerPossibleAnswer, opt => opt.MapFrom(src => src.PossibleAnswer));
            CreateMap<Common.Models.Entities.VDS.PossibleAnswer, ProposalFormQuestionAnswerPossibleAnswer>();

            CreateMap<Common.Models.Entities.VDS.Question, Models.Insurance.Question>()
                .ForMember(dest => dest.QuestionType, opt => opt.MapFrom(src => src.QuestionType));

            CreateMap<Common.Models.Entities.VDS.QuestionType, Models.Insurance.QuestionType>();

            CreateMap<Common.Models.Entities.VDS.ProposalSection, Models.ProposalForm.ProposalFormSection>()
                .ForMember(dest => dest.Section, opt => opt.MapFrom(src => src.Section))
                .ForMember(dest => dest.Questions, opt => opt.MapFrom(src => src.ProposalQuestion));

            CreateMap<Common.Models.Entities.VDS.ProposalQuestion, Models.ProposalForm.ProposalFormQuestion>()
                .ForMember(dest => dest.Question, opt => opt.MapFrom(src => src.Question))
                .ForMember(dest => dest.QuestionAnswers, opt => opt.MapFrom(src => src.ProposalQuestionAnswer));

            CreateMap<Common.Models.Entities.VDS.Proposal, ProposalForm>()
                .ForMember(dest => dest.ProposalFormSections, opt => opt.MapFrom(src=> src.VdsProposalSection));

        }
    }

Also adding .ReverseMap() creates a reverse mapping

CreateMap<Common.Models.Entities.VDS.QuestionType, Models.Insurance.QuestionType>().ReverseMap();

Startup.cs

In startup.cs -> ConfigurationServices add these lines after services.AddMvc

  var autoMapperConfig = new AutoMapper.MapperConfiguration(c =>
            {
                c.AddProfile(new ApplicationProfile());
            });
            var mapper = autoMapperConfig.CreateMapper();
            services.AddSingleton(mapper);

usage

inject as IMapper mapper

public MakesController(VegaDbContext context, IMapper mapper)
...

Map like below. First parameter is source second is target and in parentheses, we provide the object

this.mapper.Map<Models.ProposalForm.ProposalForm>(proposal);

this.mapper.Map<target>(source);

⚠️ Important for AutoMapper 12+ / 13+ / 15+ / 16+

Recent versions of AutoMapper merged or changed DI behavior. Depending on your exact version:

If you're using AutoMapper ≥ 13, you may not need the extensions package anymore.

In that case, the correct usage is:

builder.Services.AddAutoMapper(cfg =>
{
    cfg.AddProfile<ApplicationProfile>();
});