Issue Creating Mapping for join entity from DTOs

[Felix James]

Hi,

I have the following code snippet. 

I wish to save my User entity after mapping along with related entities as a single transaction. i.e. Entity framework will update the UserBranchSpecialism Table with the generated UserId as expected.

I can't find a way of specifying the User property of the UserBranchSpecialism as part of my mapping configuration i.e. I would like to specify 

// ENTITIES

public class User

{

public int Id { get; set; }

public string Name { get; set; }

public BranchProfile BranchProfile { get;set; }

}

public class BranchProfile

{

public int Id { get; set; }

public string Name { get; set; }

public List<UserBranchSpecialism> Specialisms { get; set; }

}

public class BranchSpecialism

{

public int Id { get; set; }

public string Name { get; set; }

}

public class UserBranchSpecialism

{

public User User { get; set; }

public BranchSpecialism BranchSpecialism { get;set; }

public int BranchSpecialismId { get;set; }

public int UserId { get; set; }

}

// DTOS

public class UserCreateDto

{

public string Name { get;set; }

}

public class BranchProfileDto

{

public string Name { get;set; }

public List<int> BranchSpecialismIds { get;set; }

}

// MAPPING CONFIG

CreateMap<UserCreateDto, User>();

CreateMap<BranchProfileDto, BranchProfile>()

.ForMember(dest => dest.Specialisms,

opt => opt.MapFrom(src => src.BranchSpecialismIds

.Select(id => new UserBranchSpecialism() { BranchSpecialismId = id }).ToList()));

Ideally,

I will like to do something like this:

// MAPPING CONFIG

CreateMap<UserCreateDto, User>();

CreateMap<BranchProfileDto, BranchProfile>()

.ForMember(dest => dest.Specialisms,

opt => opt.MapFrom(src => src.BranchSpecialismIds

.Select(id => new UserBranchSpecialism() { BranchSpecialismId = id, User = ???? }).ToList()));

How can i achieve with the mappings split out as above or using any other alternative means?

Thanks in advance.