c# - Linq 匿名类型成员必须在子查询中声明

Question

我正在尝试转换 this对 Linq 的 SQL 查询，以在 asp MVC 中的 View 中返回，

Linq 中的预期输出:

TotalPoints Name

  231       John 

我在第二个选择新的子查询中得到这个错误:

Invalid expression term '.'

Invalid anonymous type member declarator. Anonymous type members must be declared with a member assignment, simple name or member access.

到目前为止的 Linq 查询:

public ActionResult UserTotal()
        {
            List<TotalPointsUser> onetotal = from t in (
    (from LoyaltyDetailsTable in dbpoints.LoyaltyDetailsTable
    where
      LoyaltyDetailsTable.CustomerTable.CustomerId == 1
    group new {LoyaltyDetailsTable.CustomerTable, LoyaltyDetailsTable.LoayaltyPointsTable} by new {
      LoyaltyDetailsTable.CustomerTable.Name,
      LoyaltyPointsId = LoyaltyDetailsTable.LoayaltyPointsTable.LoyaltyPointsId,
      Points = LoyaltyDetailsTable.LoayaltyPointsTable.Points,
      CustomerId = LoyaltyDetailsTable.CustomerTable.CustomerId
    } into g
    select new TotalPointsUser{
      CustomerId = 
      g.Key.LoyaltyPointsId == 4 ? 
        (from RedeemPointsTable in dbpoints.RedeemPointsTable
        where
          RedeemPointsTable.CustomerId == 1
        select new {
          RedeemPointsTable.Amount
        }).Count(p => p.Amount != null) : g.Count(p => p.CustomerTable.CustomerId != null),
      Name=g.Key.Name,
      Points = 
      g.Key.LoyaltyPointsId == 4 ? (
        (from RedeemPointsTable in dbpoints.RedeemPointsTable
        where
         RedeemPointsTable.CustomerId == 1
        select new {
         RedeemPointsTable.Amount
        }).Sum(p => p.Amount) * g.Key.Points) : g.Sum(p => p.LoayaltyPointsTable.Points)
    }))
select new {
  CustomerId = t.Sum(p => p.CustomerId),        // here is the error
  Points= t.Sum(p => p.Points),                // and here
  Name = 
    ((from CustomerTable in dbpoints.CustomerTable
    where
      CustomerTable.CustomerId == 1
    select new {
      CustomerTable.Name
    }).First().Name)
}
           .ToList();
            return View(onetotal);
}

模型类:

public class TotalPointsUser
{
    public int CustomerId { get; set; }
    public string Name { get; set; }
    public int Points { get; set; }
}

我是 linq 的新手，我可以知道必须进行哪些更改吗？

Ant 的帮助会很棒。

Answer 1

您的查询结构是:

from t in (
)
select new {
  Column1 = .Sum(p => p.TotalUserActions),        // here is the error
  Column2 = .Sum(p => p.AllTotalPoints),    // and here
}

您必须在结果中使用 t 别名，如下所示:

from t in (
)
select new {
  Column1 = t.Sum(p => p.TotalUserActions),
  Column2 = t.Sum(p => p.AllTotalPoints),
}

但是您的结果查询中必须有这样的字段，目前情况并非如此。

我认为您应该用 SQL 编写查询，然后逐步将其传输到 LINQ。现在它非常困惑并且产生错误。

---

更新:
您遇到错误是因为您的代码不包含此类文件。什么应该包含字段 TotalUserActions 和 AllTotalPoints？尝试对所有 Points 字段求和，但无法说明 TotalUserActions 是什么:

from t in (
)
select new {
  Column1 = t.Sum(p => p.TotalUserActions),
  Column2 = t.Sum(p => p.Points),
}