AutoMapper 实体间的相互转换 对象-对象映射器

   在startup 中注册  一下让全局生效

           {
                services.AddAutoMapper(options =>
                {
                    options.AddProfile<AutoMapConfig>();
                });
            }    

在   AutoMapConfig   中配置映射规则

 public class AutoMapConfig : Profile
    {

        //映射规则
        public AutoMapConfig()
        {
            CreateMap<PageResult<Commodity>, PagingData<CommodityDTO>>()
                //                 来源实体               目标实体
                .ForMember(c => c.PageIndex, s => s.MapFrom(c => c.PageIndex))
                        //        目标字段                     来自字段
                .ForMember(c => c.PageSize, s => s.MapFrom(c => c.PageSize))
                .ForMember(c => c.RecordCount, s => s.MapFrom(c => c.TotalCount))
                .ForMember(c => c.DataList, s => s.MapFrom(c => c.DataList))
                .ReverseMap();   //这句是支持相互转换的.
            //如果属性名称相同其实是可以不用写，如果写了也更好
                 CreateMap<Commodity, CommodityDTO>()
                .ForMember(c => c.Id, s => s.MapFrom(c => c.Id))
                .ForMember(c => c.ImageUrl, s => s.MapFrom(c => c.ImageUrl))
                .ForMember(c => c.Price, s => s.MapFrom(c => c.Price))
                .ForMember(c => c.ProductId, s => s.MapFrom(c => c.ProductId))
                .ForMember(c => c.Title, s => s.MapFrom(c => c.Title))
                .ForMember(c => c.Url, s => s.MapFrom(c => c.Url))
                .ForMember(c => c.CategoryId, s => s.MapFrom(c => c.CategoryId));
        }
    }

使用

  private IMapper _IMapper = null;
   this._IMapper = mapper;
//注入进来

 PagingData<CommodityDTO> model = _IMapper.Map<PageResult<Commodity>, PagingData<CommodityDTO>>(data);

实体

 public class PageResult<T>
    {
        public int TotalCount { get; set; }
        public int PageIndex { get; set; }
        public int PageSize { get; set; }
        public List<T> DataList { get; set; }
    }
 public class PagingData<T> where T : class
    {
        public int RecordCount { get; set; }

        public int PageIndex { get; set; }

        public int PageSize { get; set; }

        public List<T> DataList { get; set; }

        public string SearchString { get; set; }
    }
 public partial class Commodity
    {
        public int Id { get; set; }
        public long? ProductId { get; set; }
        public int? CategoryId { get; set; }
        public string Title { get; set; }
        public decimal? Price { get; set; }
        public string Url { get; set; }
        public string ImageUrl { get; set; }
    }
public class CommodityDTO
    {
        public int Id { get; set; }
        public long? ProductId { get; set; }
        public int? CategoryId { get; set; }
        [Required(ErrorMessage = "Title不能为空")]
        [StringLength(500,ErrorMessage ="最长只能是500长度")]
        public string Title { get; set; }
        public decimal? Price { get; set; }
        [Required(ErrorMessage = "Url不能为空")]
        [StringLength(1000)]
        public string Url { get; set; }
        [StringLength(1000)]
        public string ImageUrl { get; set; }
    }

 C# 中的自动映射器及其示例 - 点网教程 (dotnettutorials.net)