.Net Core3.0 WebApi 項目框架搭建 十：使用AutoMapper實現模型映射

.Net Core3.0 WebApi 項目框架搭建：目錄

 

不使用AutoMapper

Model層的viewmodel文件夾新建UserViewModel.cs

    public class UserViewModel
    {
        /// <summary>
        /// ID
        /// </summary>
        public int UserId { get; set; }

        /// <summary>
        /// 用戶名
        /// </summary>
        public string UserName { get; set; }

        /// <summary>
        /// 年齡
        /// </summary>
        public int? Age { get; set; }

        /// <summary>
        /// 生日
        /// </summary>
        public string Birthday { get; set; }


        /// <summary>
        /// 手機
        /// </summary>
        public string Phone { get; set; }

        /// <summary>
        /// 地址
        /// </summary>

        public string Address { get; set; }
    }

IUserServices.cs和 類UserServices.cs中，添加GetUserDetails()方法，返回類型是UserViewModel

    public interface IUserService : IBaseService<User>
    {
        /// <summary>
        /// 獲取用戶數量
        /// </summary>
        /// <returns></returns>
        Task<int> GetCount();

        /// <summary>
        /// 獲取用戶詳情
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        Task<UserViewModel> GetUserDetails(int id);

    }

        public async Task<UserViewModel> GetUserDetails(int id)
        {
            var userinfo = await userDal.QueryByID(id);

            if (userinfo != null)
            {
                UserViewModel model = new UserViewModel()
                {
                    UserId = userinfo.UserId,
                    UserName = userinfo.UserName,
                    Address = "北京市xx區xx小區",
                    Age = userinfo.Age,
                    Birthday = "1996-06-26",
                    Phone = "13888888888"

                };
                return model;

            }
            else
            {
                return null;
            }
        }

因為我這邊只是寫了個demo，實體類字段還不是很多，真正的開發起來肯定有很多個字段，而且這種方法系統會有很多，寫起來也很累人，后期維護也不方便，要多一個字段少一個字段，要去每個地方去修改。

什么是AutoMapper

它是一種對象與對象之間的映射器，讓AutoMapper有意思的就是在於它提供了一些將類型A映射到類型B這種無聊的實例，只要B遵循AutoMapper已經建立的慣例，那么大多數情況下就可以進行相互映射了。

引入 AutoMapper 的相關包

Services項目中引用Nuget包，AutoMapper 和 AutoMapper.Extensions.Microsoft.DependencyInjection，AutoMapper.Extensions.Microsoft.DependencyInjection，這個是用來配合依賴注入的。

添加映射文件 CustomProfile.cs

 在接口層Blog.Core 中，添加文件夾AutoMapper，然后添加映射配置文件 CustomProfile.cs，用來匹配所有的映射對象關系。

    public class CustomProfile : Profile
    {
        /// <summary>
        /// 配置構造函數，用來創建關系映射
        /// </summary>
        public CustomProfile()
        {
            CreateMap<User, UserViewModel>();
        }
    }

Startup中，注入服務

services.AddAutoMapper(typeof(Startup));

修改Service層

修改上邊UserServices.cs 中GetUserDetails方法中的賦值，改用AutoMapper，並用構造函數注。

        private readonly IUserRepository userDal;
        private readonly IMapper iMapper;
        public UserService(IBaseRepository<User> baseRepository, IUserRepository userRepository, IMapper IMapper) : base(baseRepository)
        {
            userDal = userRepository;
            iMapper = IMapper;

        }

        public async Task<UserViewModel> GetUserDetails(int id)
        {
            var userinfo = await userDal.QueryByID(id);

            if (userinfo != null)
            {
                //UserViewModel model = new UserViewModel()
                //{
                //    UserId = userinfo.UserId,
                //    UserName = userinfo.UserName,
                //    Address = "北京市xx區xx小區",
                //    Age = userinfo.Age,
                //    Birthday = "1996-06-26",
                //    Phone = "13888888888"

                //};
                UserViewModel model = iMapper.Map<UserViewModel>(userinfo);
                model.Address = "北京市xx區xx小區";
                model.Birthday = "1996-06-26";
                model.Phone = "13888888888";
                return model;

            }
            else
            {
                return null;
            }
        }

測試AutoMapper

添加一個接口測試automapper

 

        /// <summary>
        /// 測試automapper
        /// </summary>
        /// <returns></returns>
        [HttpGet]
        public async Task<IActionResult> AutoMapper(int id)
        {
            var userinfo = await _userService.GetUserDetails(id);

            return Ok(userinfo);
        }

 

F5運行調試，可以看到斷點處已經轉換成功了

復雜深拷貝映射

 

 有的小伙伴會問，你這個這個簡單，都是相同字段的，那當然很方便啦，要是一個復雜的，比如屬性名字不一樣的，或者說有子類等嵌入型的咋辦？放心，一樣是可以的。

 

1、屬性名稱不一樣

   CreateMap<Student, StudentViewModel>()
       .ForMember(d => d.CountyName, o => o.MapFrom(s => s.County))
       .ForMember(d => d.ProvinceName, o => o.MapFrom(s => s.Province));

2、如果是還有子類的復雜類型

CreateMap<Student, StudentViewModel>()
      .ForMember(d => d.County, o => o.MapFrom(s => s.Address.County))
      .ForMember(d => d.Province, o => o.MapFrom(s => s.Address.Province))
      .ForMember(d => d.City, o => o.MapFrom(s => s.Address.City))
      .ForMember(d => d.Street, o => o.MapFrom(s => s.Address.Street))
      ;


   public class Student : Entity
    {
        public string Name { get; private set; }
        public string Email { get; private set; }
        public string Phone { get; private set; }
        public DateTime BirthDate { get; private set; }
        public Address Address { get; private set; }
    }

    public class StudentViewModel
    {
        public Guid Id { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }
        public DateTime BirthDate { get; set; }
        public string Phone { get; set; }
        public string Province { get; set; }
        public string City { get; set; }
        public string County { get; set; }
        public string Street { get; set; }
    }