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, 如果使用屬性意一一對應, 不免會有大量的工作量 |
好了,接下來直接上代碼來說明。
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EmployeeProfile類, 繼承於Profile。
public class EmployeeProfile: Profile { public EmployeeProfile() { CreateMap() .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> CreateEmployeeForCompany(Guid companyId, EmployeeAddDto employee) { if (!await _companyRepository.CompanyExistsAsync(companyId)) { return NotFound(); } var entity = _mapper.Map(employee); _companyRepository.AddEmployee(companyId, entity); await _companyRepository.SaveAsync(); var dtoToReturn = _mapper.Map(entity); return CreatedAtRoute(nameof(GetEmployeeForCompany), new { companyId = companyId, employeeId = dtoToReturn.Id }, dtoToReturn); } }
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