如何将数据从ef查询分配给视图模型

Question

我正在编写一个get请求api，我想从数据库中获取记录，然后在视图模型中分配选定的字段。 请教我如何使用投影创建查询并为模型分配值

我创建了一个perent模型，该模型对其所有子实体都具有导航属性。 使用dbcontext，我已经成功地将数据分配到变量中，而将其分配给模型约束错误。 还请告诉我如何获取每种津贴类型比率下所有雇员的总和

处理程序代码

 try
            {
                var predicate = PredicateBuilder.True<PreRevisionRegularEmployee>();
                var model = new PayBillListView();
                int SectionId = request.SectionId;
                PayBillViewModel payBillViewModel = new PayBillViewModel();
                DateTime paydate = string.IsNullOrEmpty(request.Date) ? DateTime.Now : Convert.ToDateTime(request.Date);
                predicate = predicate.And(x => x.BasicDetail.SectionId == SectionId);


                IList<PayBillViewModel> payBill = await _context.PreRevisionRegularEmployees.Where(predicate)

                                               .Select(c => new PayBillViewModel
                                               {
                                                   PreRevisionRegularEmployeeId = c.PreRevisionRegularEmployeeId,
                                                   CPFNumber = c.CPFNumber,
                                                   GPFNumber = c.GPFNumber,
                                                   percentageAllowanceTypeName = c.PreRevisionRegularEmployeePercentageAllowanceTypes.Select(pa => pa.PercentageAllowanceType.Name),
                                                   PercentageAllowanceRate =(IEnumerable<PercentageAllowance>) c.PreRevisionRegularEmployeePercentageAllowanceTypes.Select(par => par.PercentageAllowanceType.PercentageAllowances.Select(p=>p.Rate)),
                                                   Probation = c.BasicDetail.Probation


                                                })

                                                          .ToListAsync();
                model.payBillViewModels = _mapper.Map <IList<PayBillViewModel>>(payBill);




                return model;

            }
            catch (Exception)
            {

                throw;
            }

主实体

 public class PreRevisionRegularEmployee: BaseEntity
    {
        public int PreRevisionRegularEmployeeId { get; set; }
        //public DateTime CreatedAt { get; set; }
        //public string CreatedBy { get; set; }
        //public DateTime ModifiedAt { get; set; }
        //public string ModifiedBy { get; set; }

        public string GPFNumber { get; set; }
        public string CPFNumber { get; set; }
        public string GospedCode { get; set; } // 14-digit code

        public string EmployeeCode
        {
            get
            {
                return string.IsNullOrEmpty(GPFNumber) ? 
                    (string.IsNullOrEmpty(CPFNumber) ? GospedCode : CPFNumber) : GPFNumber;
            }
        }
        public int EmployeeClass { get; set; }
        public bool GovernmentAccomodation { get; set; }
        public string AccomodationClass { get; set; }
        public bool VehicleAttached { get; set; }
        public BasicDetail BasicDetail { get; set; }
        public AppointmentOrder AppointmentOrder { get; set; }
        public ICollection<PreRevisionRegularEmployeePercentageAllowanceType> PreRevisionRegularEmployeePercentageAllowanceTypes { get; set; }

 public class PreRevisionRegularEmployeePercentageAllowanceType
    {
        public int PreRevisionRegularEmployeeId { get; set; }
        public PreRevisionRegularEmployee PreRevisionRegularEmployee { get; set; }
        public int PercentageAllowanceTypeId { get; set; }
        public PercentageAllowanceType PercentageAllowanceType { get; set; }
    }

 public class PercentageAllowanceType : BaseLookup
    {
        public int PercentageAllowanceTypeId { get; set; }
        public ICollection<PercentageAllowance> PercentageAllowances { get; set; }
        public ICollection<PreRevisionRegularEmployeePercentageAllowanceType> PreRevisionRegularEmployeePercentageAllowanceTypes { get; set; }
    }

 public class PercentageAllowance : BaseEntity
    {
        public int PercentageAllowanceId { get; set; }
        public int RevisedPayRevision { get; set; }
        public DateTime EffectiveDateFrom { get; set; }
        public float Rate { get; set; }
        public int PercentageAllowanceTypeId { get; set; }
        public PercentageAllowanceType PercentageAllowanceType { get; set; }

    }