WHERE子句中的Dapper和DateTime会导致多个映射的null

Question

我终于能够构造一个多映射查询并返回有意义的数据。此查询返回了一个自定义对象的列表，该对象本身由一些其他对象组成。但是这个查询只使用了一个参数。

当我通过添加第二个参数DateTime修改这个查询时，两个聚合对象（Part和Color）为null。然而，当我在探查器中捕获SQL并在SQL Server中运行它时，所有的数据都在那里！

如何更好地处理where子句中的DateTime参数？很明显，正是这个原因造成了问题。

下面的代码适用于注释掉的where子句，但不适用于现有的子句。

  public IList<PartReceipt> GetReceiptHistory(ListItem supplier, DateTime dateReceived)
  {
     const string sql =
        @"SELECT r.id,  r.Quantity, r.UnitCost, r.DateReceived,
                 s.Id , s.Description, 
                 p.Id, p.Number, p.Description, p.StockClass,
                 mp.Id , mp.Number, mp.ManufacturerId, mp.Description,
                 m.Id , m.Description, m.ShortDescription, 
                 c.Id, c.Description, 
                 pc.Id, pc.Name, pc.Description
          FROM   PartReceipt r
          INNER JOIN Supplier s ON r.SupplierId = s.Id
          INNER JOIN Part p on r.PartId = p.Id
          INNER JOIN ManufacturerPart mp ON p.ManufacturerPartId=mp.Id
          INNER JOIN Manufacturer m ON mp.ManufacturerId = m.Id
          LEFT JOIN Color c ON p.ColorId=c.Id
          LEFT JOIN ProductCategory pc ON p.ProductCategoryId=pc.Id
          WHERE s.Id=@supplierId AND r.DateReceived = @dateReceived";
     //           WHERE s.Id=@supplierId";
     IList<PartReceipt> reportData;
     using (DbConnection connection = ConnectionFactory.GetOpenConnection())
     {
        reportData = connection.Query<PartReceipt>(sql,
           new
           {
              supplierId = supplier.Id,
              dateReceived
           }).ToList();
     }
     return reportData;
  }  

支持类包括：

  public class PartReceipt
  {
     public int Id { get; set; }
     public Supplier Supplier { get; set; }
     public Part Part { get; set; }
     public DateTime DateReceived { get; set; }
     public Decimal UnitCost { get; set; }
     public int Quantity { get; set; }
  }   
  public class Part
  {
     public Color Color { get; set; }
     public string Description { get; set; }
     public int Id { get; set; }
     public ManufacturerPart ManufacturerPart { get; set; }
     public string Number { get; set; }
     public string PicturePath { get; set; }
     public ProductCategory ProductCategory { get; set; }
     public string StockClass { get; set; }
  }
  public class ManufacturerPart
  {
     public string Description { get; set; }
     public int Id { get; set; }
     public int ManufacturerId { get; set; }
     public string Number { get; set; }
     public Manufacturer Parent { get; set; }
  }   
  public class Manufacturer
  {
     public string Description { get; set; }
     public int Id { get; set; }
     public string ShortDescription { get; set; }
  }   
  public class ProductCategory
  {
     public string Description { get; set; }
     public int Id { get; set; }
     public string Name { get; set; }
  }   
  public class Color
  {
     public string Description { get; set; }
     public int Id { get; set; }
  }  

Answer 1

很抱歉我在发布这个问题之前没有更加小心。我没有正确构造多映射查询。当我这样做的时候，它是有效的。

  public IList<PartReceipt> GetReceiptPart(ListItem supplier, DateTime dateReceived)
  {
     const string sql =
        @"SELECT r.id,  r.Quantity, r.UnitCost, r.DateReceived,
                 s.Id , s.Description, 
                 p.Id, p.Number, p.Description, p.StockClass,
                 mp.Id , mp.Number, mp.ManufacturerId, mp.Description,
                 m.Id , m.Description, m.ShortDescription, 
                 c.Id, c.Description, 
                 pc.Id, pc.Name, pc.Description
          FROM   PartReceipt r
          INNER JOIN Supplier s ON r.SupplierId = s.Id
          INNER JOIN Part p on r.PartId = p.Id
          INNER JOIN ManufacturerPart mp ON p.ManufacturerPartId=mp.Id
          INNER JOIN Manufacturer m ON mp.ManufacturerId = m.Id
          LEFT JOIN Color c ON p.ColorId=c.Id
          LEFT JOIN ProductCategory pc ON p.ProductCategoryId=pc.Id
          WHERE s.Id=@supplierId AND r.DateReceived = @dateReceived";
     IList<PartReceipt> reportData;
     using (DbConnection connection = ConnectionFactory.GetOpenConnection())
     {
        reportData =
         connection
            .Query
            <PartReceipt, Supplier, Part, ManufacturerPart, Manufacturer, Color, ProductCategory, PartReceipt>(
               sql,
               (receipt, supp, part, mfgPart, mfg, color, productCategory) =>
               {
                  receipt.Supplier = supp;
                  receipt.Part = part;
                  receipt.Part.ManufacturerPart = mfgPart;
                  receipt.Part.ManufacturerPart.Parent = mfg;
                  receipt.Part.Color = color;
                  receipt.Part.ProductCategory = productCategory;
                  return receipt;
               }, new { supplierId = supplier.Id, dateReceived })
            .ToList();
     }
     return reportData;
  }