使用自动映射器将数据库实体映射到DTO

Question

I am using AutoMapper. I am facing an issue regarding mapping my DTO to database entity. I want to update my existing data in the database by mapping my updated DTO to DB Entity using AutoMapper rather to manually map the DTO to DB Entity.

Answer 1

First of all define your DTO related to the entity. For example

public class Author {
    public string Name { get; set; }
}

public class Book {
    public string Title { get; set; }
    public Author Author { get; set; }
}

public class BookDTO {
    public string Title { get; set; }
    public string Author { get; set; }
}

Then init your Automap somewhere in your application startup code:

AutoMapper.Mapper.CreateMap<Book, BookDTO>()
    .ForMember(dest => dest.Author,
           opts => opts.MapFrom(src => src.Author.Name));

AutoMapper.Mapper.CreateMap<Book, BookDTO>().ReverseMap()

Now and example of an update method froma the DTO to the entity:

    public int Update(BookDTO dto) {
        var entity = _context.Books.FindAsync(dto.id);
        if (entity == null) throw new ItemNotFoundException(dto.id);
        AutoMapper.Mapper.Map(dto, entity)
        return _context.SaveChanges();
    }

And another example for the insert:

    public int Insert(BookDTO dto) {
        var entity = AutoMapper.Mapper.Map<Book>(dto);
        _context.Provinces.Add(entity);
        return _context.SaveChanges();
    }

More info on http://cpratt.co/using-automapper-getting-started/