Map List to List

Question

How do I use automapper to map a list of identity users to a list dto?

I'm having difficulty getting my automapper to map a list of identity users to a dto. I pull the user list with a lengh > 0, but when I map it, it becomes an empty list. Here is my code.

startup.cs

 public void ConfigureServices(IServiceCollection services)
        {
     var mappingConfig = new MapperConfiguration(mc =>
            {
                mc.AddProfile(new MappingProfile());
            });
     IMapper mapper = mappingConfig.CreateMapper();
            services.AddSingleton(mapper);
}

MappingProfile.cs

public class MappingProfile : Profile
    {
        public MappingProfile()
        {
            // Add as many of these lines as you need to map your objects

            CreateMap<User, userReponseDto>()
            .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id));
            ;
            CreateMap<List<User>, IEnumerable<userReponseDto>>();
            CreateMap<List<User>, List<userReponseDto>>();
        }
    }

userReponseDto.cs

public class userReponseDto
    {
        public string Id { get; set; }
        public DateTimeOffset? LockoutEnd { get; set; }
        //
        // Summary:
        //     Gets or sets a flag indicating if two factor authentication is enabled for this
        //     user.
        public bool TwoFactorEnabled { get; set; }
        //
        // Summary:
        //     Gets or sets a flag indicating if a user has confirmed their telephone address.
        public bool PhoneNumberConfirmed { get; set; }
        //
        // Summary:
        //     Gets or sets a telephone number for the user.
        public string PhoneNumber { get; set; }
        //
        // Summary:
        //     A random value that must change whenever a user is persisted to the store
        public string ConcurrencyStamp { get; set; }

        // Summary:
        //     Gets or sets a flag indicating if a user has confirmed their email address.
        public bool EmailConfirmed { get; set; }

        // Summary:
        //     Gets or sets the email address for this user.
        public string Email { get; set; }

        // Summary:
        //     Gets or sets the user name for this user.
        public string UserName { get; set; }

        // Summary:
        //     Gets or sets a flag indicating if the user could be locked out.
        public bool LockoutEnabled { get; set; }
        //
        // Summary:
        //     Gets or sets the number of failed login attempts for the current user.
        public int AccessFailedCount { get; set; }
    }

User.cs

public class User : IdentityUser
    {
    }

ApplicationDbContext.cs

        public DbSet<User> ApplicationUsers { get; set; }

UsersController.cs

    public class UsersController : ControllerBase{
            private readonly ApplicationDbContext _context;

            private readonly IMapper _mapper;
            public UsersController(IMapper mapper,ApplicationDbContext context)
        {
            _mapper = mapper;
            _context = context;
        }

 [HttpPost]
        public IActionResult GetUsers()
        {

                    // return Ok(_context.ApplicationUsers.ToList());
                    var list = _context.ApplicationUsers.ToList();
                    IEnumerable<userReponseDto> userList ;
                    var response = _mapper.Map<List<userReponseDto>>(list);
                    // var response =
                    userList= list.Select(_mapper.Map<IdentityUser, userReponseDto>);

                    return Ok(userList);

        }

}

You don't need to configure `List`, it already understands `List`. — ProgrammingLlama, Jul 25 '19 at 05:15
I think declaring the map for the list is what called it to fail to map. — lastlink, Jul 25 '19 at 05:20

score 4 · Answer 1 · answered Jul 25 '19 at 05:19

I was able to determine that you shouldn't define maps per lists as per Automapper mapping list becomes 0 @darin-dimitrov. I thought this was due to nested attributes in the identity user. So my mapping profile becomes.

        CreateMap<User, userReponseDto>()
           .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id));
        CreateMap<IdentityUser, userReponseDto>()
           .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.Id));

With no list maps declared. Then

var list = _context.ApplicationUsers.ToList();
var response = _mapper.Map<List<userReponseDto>>(list);

now works properly.

If the property name and the type are the same in both the entity and the Dto, you do not need to explicitly map. It's picked up by default. — kovac, Jul 25 '19 at 05:56

Map List to List

How do I use automapper to map a list of identity users to a list dto?

1 Answers1