[花裏胡哨].net Dto映射

我們假設一個場景, 採用EF Core+Web Api, 這時候可能會出現EF Core中的Entity Model和在項目中使用的Model之間對應關係出現偏差, 上代碼

EntityModels.Employee.cs

    public class Employee
    {
        public Guid Id { get; set; }
        public Guid CompanyId { get; set; }

        public string EmployeeNo { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public Gender Gender { get; set; }
        public DateTime DateOfBirth { get; set; }

        public Company Company { get; set; }
    }

Models.EmployeeDto.cs

    public class EmployeeDto
    {
        public Guid Id { get; set; }
        public Guid CompanyId { get; set; }

        public string EmployeeNo { get; set; }
        public string Name { get; set; }
        public string GenderDisplay { get; set; }
        public int Age { get; set; }
    }

我們可以觀察到, 兩個實體之間有很多不同的地方, 比如名字拆分啊, 出生日期和年齡啊等等, 我之前的做法就是硬生生手寫代碼轉換, 但是經過學習大佬們的代碼, 發現了一個類庫, 在此算是記錄一下吧

AutoMapper.Extensions.Microsoft.DependencyInjection

可以通過Nuget安裝

使用的時候也非常簡單, 建立Profile文件夾, 新建一個EmployeeProfie類, 繼承於Profile

    public class EmployeeProfile: Profile
    {
        public EmployeeProfile()
        {
            CreateMap<Employee, EmployeeDto>()
                .ForMember(dest => dest.Name,
                    opt => opt.MapFrom(src => $"{src.FirstName} {src.LastName}"))
                .ForMember(dest => dest.GenderDisplay,
                    opt => opt.MapFrom(src => src.Gender.ToString()))
                .ForMember(dest => dest.Age,
                    opt => opt.MapFrom(src => DateTime.Now.Year - src.DateOfBirth.Year));
        }
    }

在使用的時候只需要這樣, 注入mapper, 然後就是很簡單的操作了, 簡直了, 功能非常強大!!!

    [ApiController]
    [Route("api/companies/{companyId}/employees")]
    public class EmployeesController: ControllerBase
    {
        private readonly IMapper _mapper;
        private readonly ICompanyRepository _companyRepository;

        public EmployeesController(IMapper mapper, ICompanyRepository companyRepository)
        {
            _mapper = mapper ?? throw new ArgumentNullException(nameof(mapper));
            _companyRepository = companyRepository ?? throw new ArgumentNullException(nameof(companyRepository));
        }
        [HttpPost]
        public async Task<ActionResult<EmployeeDto>>
            CreateEmployeeForCompany(Guid companyId, EmployeeAddDto employee)
        {
            if (!await _companyRepository.CompanyExistsAsync(companyId))
            {
                return NotFound();
            }

            var entity = _mapper.Map<Employee>(employee);

            _companyRepository.AddEmployee(companyId, entity);
            await _companyRepository.SaveAsync();

            var dtoToReturn = _mapper.Map<EmployeeDto>(entity);

            return CreatedAtRoute(nameof(GetEmployeeForCompany), new
            {
                companyId = companyId,
                employeeId = dtoToReturn.Id
            }, dtoToReturn);
        }
    }