Entity Framework 5 方法查询汇总答案

【问题标题】：Entity Framework 5 Method Query Roll UpEntity Framework 5 方法查询汇总
【发布时间】：2013-03-20 20:03:24
【问题描述】：

我正在尝试通过查询 SaleConfirmation 表来获取已确认/已完成购买的摘要，但我在方法语法查询方面遇到了很多困难。

数据库表
这是存储最终销售额的 SaleConfirmation 表结构。

Id   OfferId   ProdId      Qty    SaleDate
-------------------------------------------------------
10   7         121518      150    2013-03-14 00:00:00.000
19   7         100518      35     2013-03-18 14:46:34.287
20   7         121518      805    2013-03-19 13:03:34.023
21   10        131541      10     2013-03-20 08:34:40.287

Id：唯一的行 ID。
OfferId：链接到优惠/销售的外键表。
ProdId：产品表中产品的 ID。
数量：销售给客户的数量。
SaleDate：完成销售的日期。

控制器动作

var confRollUps = db.SaleConfirmation
                  .GroupBy(c => c.OfferId) // Ensure we get a list of unique/distinct offers
                  .Select(g => g.Select(i => new {
                            i.OfferId, 
                            i.Product.Variety, // "Category" of product, will be the same across products for this offer. i.Product is a SQL Server Navigation property.
                            i.Offer.Price, // The price of the product, set per offer. i.Offer is a SQL Server Navigation property.
                            i.Offer.Quantity, // The quantity of items that are expected to be sold before the offer expires
                            i.Offer.DateClose, // Date of when the offer expires
                            g.Sum(ii => ii.Qty) // Sum up the Qty column, we don't care about ProdIds not matching
                   }));

select查询中的错误是g.Sum(ii => ii.Qty)，错误如下。

匿名类型成员声明器无效。匿名类型成员必须使用成员分配、简单名称或成员访问来声明。

【问题讨论】：

标签： c# asp.net entity-framework asp.net-mvc-4 anonymous-types

【解决方案1】：

你只需要将匿名类型分配给一个变量，试试这个。

var confRollUps = db.SaleConfirmation
              .GroupBy(c => c.OfferId) // Ensure we get a list of unique/distinct offers
              .Select(g => g.Select(i => new {
                        OfferId = i.OfferId, 
                        ProductVariety = i.Product.Variety, // "Category" of product, will be the same across products for this offer. i.Product is a SQL Server Navigation property.
                        OfferPrice = i.Offer.Price, // The price of the product, set per offer. i.Offer is a SQL Server Navigation property.
                        OfferQty = i.Offer.Quantity, // The quantity of items that are expected to be sold before the offer expires
                        OfferDateClose =i.Offer.DateClose, // Date of when the offer expires
                        Total =g.Sum(ii => ii.Qty) // Sum up the Qty column, we don't care about ProdIds not matching
               }));

【讨论】：