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AutoMapper for many relationships in the collection

I am trying to map objects to a collection through a table of many of many, using AutoMapper.

My domain model (Entity Framework) looks like this:

public class User
{
    public int UserID { get; set; }
    public string Name { get; set; }        
    public IList<UserCompany> UserCompanies { get; set; }
}

public class Company
{
    public int CompanyID { get; set; }
    public string Name { get; set; }
}

public class UserCompany
{
    public int UserCompanyID { get; set; }
    public int UserID { get; set; }
    public int CompanyID { get; set; }
}

I am trying to map a class that looks like this:

public class CompanyDTO
{
    public int CompanyID { get; set; }
    public string Name { get; set; }
}

public class UserDTO
{
    public int UserID { get; set; }
    public string Name { get; set; }
    public IList<CompanyDTO> Companies { get; set; }
}

My current mapping configuration looks like this:

Mapper.CreateMap<Company, CompanyDTO>(); //works no problem

Mapper.CreateMap<User, UserDTO>()
    .ForMember( dto => dto.Companies,
    opt => opt.MapFrom(x => Mapper.Map<IList<Company>, IList<CompanyDTO>>(x.UserCompanies.Select( y => y.Company ).ToList())));

Arguing that the configuration validly returns true, but when I try to actually map the user into UserDTO, I get: The signature of the body and the declaration in the implementation of the method does not match.

If I use AfterMap and manually move each company to the list of companies, it will work, but it seems to me that I can deal with this as part of creating a map.

In my query, to get one user from the database I including the UserCompany.Company navigation property and I can quickwatch and see what is returned.

+5
1

. - :

Mapper.CreateMap<User, UserDTO>()
    .ForMember(dto => dto.Companies, opt => opt.MapFrom(x => x.UserCompanies));

UserCompany:

Mapper.CreateMap<UserCompany, CompanyDTO>();

, CompanyDTO, .

, , IList , IList. , , : https://github.com/AutoMapper/AutoMapper/wiki/Custom-value-resolvers

2

, . ValueResolver .

Mapper.CreateMap<Company, CompanyDTO>();
Mapper.CreateMap<User, UserDTO>()
    .ForMember(dto => dto.Companies, opt => opt.ResolveUsing<CompanyResolver>());
Mapper.AssertConfigurationIsValid();

CompanyResolver - -

public class CompanyResolver : ValueResolver<User, IList<CompanyDTO>>
{
    protected override IList<CompanyDTO> ResolveCore(User source)
    {
        return source.UserCompanies
            .Select(userCompany =>
                    Mapper.Map<Company, CompanyDTO>(companies.FirstOrDefault(x => x.CompanyID == userCompany.CompanyID)))
            .ToList();
    }
}
+6

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