c# - EntityFramework Core 3 和 Automapper。包含在过滤器中

Question

我正在尝试使用 EFC3 从 IQueryable 执行 automapper ProjectTo<> 调用。我的对象有一些导航属性，我需要这样检索，但其他一些我需要使用 Where 子句进行过滤。

• 我可以通过 3 个数据库调用来实现它

          var dto = _context.Bonds.Where(x => x.Id == request.Id).
              ProjectTo<BondDto>(_mapper.ConfigurationProvider) // Mapping is done here
              .FirstOrDefaultAsync(cancellationToken); 
  
          var price = _context.MarketDatas.OfType<RatingMarketData>()
              .Where(x => x.Date == request.Date && x.AssetId == request.Id)
              .ProjectTo<RatingMarketDataDto>(_mapper.ConfigurationProvider)
              .FirstOrDefaultAsync(cancellationToken);
  
          var rating = ... same than for price
  

• 1 个数据库调用，包含很多我不喜欢的包含和映射

            var vm = _context.Bonds
              .Include(x => x.CallSchedule)
              .Include(x => x.PutSchedule)
              .Include(x => x.FixedCouponSchedule)
              .Include(x => x.FloatingCouponSchedule)
              .Include(x => x.RedemptionSchedule) // If I don't Include I don't get nested objects like ProjectTo<>
              .Where(x => x.Id == request.Id)
              .Select(b => new BondVm
              {
                  BondDto = _mapper.Map<BondDto>(b),
  
                  RatingDto = _mapper.Map<RatingMarketDataDto>(b.MarketDatas.OfType<RatingMarketData>()
                      .OrderByDescending(x => x.Date)
                      .FirstOrDefault(x => x.AssetId == request.Id && x.Date <= request.Date)),
  
                  PriceDto = _mapper.Map<PriceMarketDataDto>(
                      b.MarketDatas.OfType<PriceMarketData>()
                      .FirstOrDefault(x => x.Date == request.Date && x.AssetId == request.Id))
              })
              .FirstOrDefaultAsync(cancellationToken);
  

• 1 次数据库调用而不使用 Automapper。很多手动映射和丑陋的代码。这正是我想要实现的目标，但我想使用 Automapper projectTo<<>> 的强大功能。

          var vm = await _context.Bonds
              .Where(b => b.Id == request.Id)
              .Select(bond => new
              {
                  Bond = new BondDto
                  {
                      Id = bond.Id.ToString(),
                      Currency = bond.Currency,
                      BorrowerClass = bond.BondSector.BorrowerClass,
                      CouponFrequency = bond.CouponFrequency,
                      AccruedDayCount = bond.AccruedDayCount,
                      CallScheduleStyle = bond.CallScheduleStyle,
                      CorrelatedResidual = bond.CorrelatedResidual,
                      IsPerpetual = bond.IsPerpetual,
                      Issuer = bond.Issuer,
                      IssuerSeniority = bond.IssuerSeniority,
                      Maturity = bond.Maturity,
                      CallSchedule = bond.CallSchedule.Select(s => _mapper.Map<CallScheduleItemDto>(s)).ToList(),
                      FixedCouponSchedule = bond.FixedCouponSchedule.Select(s => _mapper.Map<FixedCouponScheduleItemDto>(s)).ToList(),
                      RedemptionSchedule = bond.RedemptionSchedule.Select(s => _mapper.Map<RedemptionScheduleItemDto>(s)).ToList(),
                      PutSchedule = bond.PutSchedule.Select(s => _mapper.Map<PutScheduleItemDto>(s)).ToList(),
                      FloatingSpreadSchedule = bond.FloatingSpreadSchedule.Select(s => _mapper.Map<FloatingSpreadScheduleItemDto>(s)).ToList(),
                  },
  
                  Price = _mapper.Map<PriceMarketDataDto>(bond.MarketDatas.OfType<PriceMarketData>()
                      .FirstOrDefault(p => p.Date == request.Date && p.AssetId == request.Id)),
  
                  Rating = _mapper.Map<RatingMarketDataDto>(bond.MarketDatas.OfType<RatingMarketData>()
                      .OrderByDescending(x => x.Date)
                      .FirstOrDefault(x => x.AssetId == request.Id && x.Date <= request.Date))})
  
              .FirstOrDefaultAsync(cancellationToken);
  

我想要实现的是使用 ProjectTo<<'BondVm'>> 的 1 个数据库调用

var vm = _context.Bonds
    .Where(x => x.Id == request.Id)
    .ProjectTo<BondVm>(_mapper.ConfigurationProvider);

这是 BondVM 以防万一：

        public class BondVm
        {
            public BondDto BondDto { get; set; }
            public RatingMarketDataDto RatingDto { get; set; }
            public PriceMarketDataDto PriceDto { get; set; }
        }

并且能够以上述条件过滤我的 2 个导航属性（评级和价格）。我不知道如何过滤我的映射配置文件

如果您需要更多信息，请与我们联系。非常感谢您的帮助！

编辑：

关于 Lucian Bargaoanu 的建议，这是我的映射配置文件：

public BondVmMapper()
            {
                Map.ForMember(d => d.BondDto, o => o.MapFrom(x => x));

                Map.ForMember(d => d.PriceDto, o => o.MapFrom(s => s.MarketDatas.OfType<PriceMarketData>()));

                Map.ForMember(d => d.RatingDto, o => o.MapFrom(s => s.MarketDatas.OfType<RatingMarketData>()));
            }

奇怪的是，我们将 Enumerable 映射到单个对象上，这应该如何工作？

标签： c#entity-framework-coreautomapper