public Flattening() { _user = new User { Name = "Anakin" }; _ticket = new Ticket { User = _user }; _article = new Article { Name = "Tabac", Price = 99.99m }; _ticket.AddTicketLineItem(_article, 8); _mapper = new MapperConfiguration(cfg => { cfg.CreateMap <Ticket, TicketDto>() .ForMember(x => x.CustomerName, x => { x.Condition(e => e.User is not null); x.MapFrom(e => e.User !.Name); }) .ReverseMap(); })