AutoMapper - 试图将我的对象 属性 展平为字符串但出现错误

Question

我正在尝试将我的 ProductDto 映射到 Product class。将 ProductDto class 中的字符串 属性 映射到 Product class 中的 Brand 属性 时出现错误。 =28=]

AutoMapper.AutoMapperMappingException: Error mapping types.

Mapping types:
ProductDto -> Product
SilksyAPI.Dto.ProductDto -> SilksyAPI.Entities.Product

Type Map configuration:
ProductDto -> Product
SilksyAPI.Dto.ProductDto -> SilksyAPI.Entities.Product

Destination Member:
Brand

 ---> AutoMapper.AutoMapperMappingException: Missing type map configuration or unsupported mapping.

Mapping types:
String -> Brand
System.String -> SilksyAPI.Entities.Brand

这是我的映射配置文件：

CreateMap<Product, ProductDto>()
    .ForMember(dest => dest.Brand, opt => opt.MapFrom(p => p.Brand.Name))
    .ForMember(dest => dest.Categories, opt => opt.MapFrom(p => p.ProductCategories.Select(pc => pc.Category.Name)));

CreateMap<ProductDto, Product>()
    .ForMember(dest => dest.Brand, opt => opt.MapFrom(src => src.Name));

Class是：

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }

    public int BrandId { get; set; }
    public Brand Brand { get; set; }

    public ICollection<ProductCategory> ProductCategories { get; set; }
}

public class Brand
{
    public int Id { get; set; }

    [Required]
    [MaxLength(100)]
    public string Name { get; set; }
}

Dto Class

 public class ProductDto
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }
    public string Brand { get; set; }
    public List<string> Categories { get; set; }

}

我尝试了不同的映射配置文件，但我无法从 ProductDto 映射到 Product，但可以毫无问题地从 Product 映射到 ProductDto。

这是我尝试过的其他一些东西

CreateMap<Brand, string>()
    .IncludeMembers(b => b.Name);


CreateMap<Product, ProductDto>()
    .ForMember(dest => dest.Brand, opt => opt.MapFrom(p => p.Brand.Name))
    .ForMember(dest => dest.Categories, opt => opt.MapFrom(p => p.ProductCategories.Select(pc => pc.Category.Name)))
    .ReverseMap();

和

Mapper.CreateMap<Brand, string>().ConvertUsing(source => source.Name ?? string.Empty);

https://docs.automapper.org/en/stable/Flattening.html

Answer 1

从您的第一个映射配置文件，当从 ProductDto 映射到 Product 时，对于 Brand 属性，您需要创建一个新的 Brand 实例如下：

cfg.CreateMap<ProductDto, Product>()
   .ForMember(dest => dest.Brand, opt => opt.MapFrom(src => new Brand { Name = src.Name }));

Sample Program

---

For .IncludeMembers()

我认为它不适合您的情况，因为您要从 object 映射到 string，而不是 object 到 object。

---

For .ConvertUsing()

您需要添加以下代码以将品牌 属性 从 string 映射到 Brand。

cfg.CreateMap<string, Brand>()
   .ConvertUsing(source => new Brand { Name = source });

Sample program (.ConvertUsing())