在C＃中的Lambda表达式组

Question

我想通过ItemNumber将我的LINQ查询分组，并返回整个表的总数为Quantity。

Example: 
ItemNumber - ItemName - Quantity 
100   Item1  1 
150   Item2  2 
100   Item1  2 
200   Item3  1 
150   Item2  2 

Should be: 
ItemNumber - ItemName - Quantity 
100   Item1  3 
150   Item2  4 
200   Item3  1 

这是我想组查询：

public IQueryable<WebsiteOrderStatus> GetOrderStatusByAccountNumberWithoutDeleted 
     (string accountNumber) 
{ 
    return db.WebsiteOrderStatus 
      .Where(x => x.AccountNumber == accountNumber && x.LastUpdatedStatus != 1); 
} 

到目前为止我最好的结果（这不可能，虽然编译）：

public IQueryable<IGrouping<Int32?, WebsiteOrderStatus>> lol(string accountNumber) 
{ 
    db.WebsiteOrderStatus 
     .Where(x => x.AccountNumber == accountNumber && x.LastUpdatedStatus != 1) 
     .GroupBy(g => g.ItemNumber) 
     .Select(g => new 
        { 
         g.Key.ItemNumber, 
         Column1 = (Int32?)g.Sum(p => p.Quantity) 
        }); 
} 

编辑：

感谢大家的回复，我必须面对它。在我看来，这些匿名类型非常难以工作，所以我找到了另一种解决方案。

我做了另一种方法，它总结了用户项目的数量并将其分组。

public IQueryable<WebsiteOrderStatus> GetOrderStatusByAccountNumberWithoutDeleted(string accountNumber) 
{ 
    return db.WebsiteOrderStatus.Where(x => x.AccountNumber == accountNumber && x.LastUpdatedStatus != 1).GroupBy(x => x.ItemNumber).Select(grp => grp.First()); 
} 

public int GetQuantityOfUsersItem(string accountNumber, string itemNumber) 
{ 
    return db.WebsiteOrderStatus.Where(x => x.ItemNumber == itemNumber && x.AccountNumber == accountNumber).Sum(x => x.Quantity); 
} 

在网页，我有我的GridView我所做的：

var query = websiteOrderStatusRep.GetOrderStatusByAccountNumberWithoutDeleted(AppSession.CurrentLoginTicket.AccountNumber).Select(x => new { x.ItemName, x.ItemNumber, x.FormatName, x.Price, x.Status, x.Levering, Quantity = websiteOrderStatusRep.GetQuantityOfUsersItem(x.AccountNumber, x.ItemNumber)}); 

Answer 1

public IQueryable<IGrouping<Int32?, WebsiteOrderStatus>> lol(string accountNumber) 
{ 
    db.WebsiteOrderStatus 
     .Where(x => x.AccountNumber == accountNumber && x.LastUpdatedStatus != 1) 
     .GroupBy(g => g.ItemNumber) 
     .Select(g => new 
        { 
         ItemNumber = g.Key, 
         ItemName = g.First().ItemName, 
         Count = g.Sum(item => item.Quantity) 
        }); 
} 

Answer 2

我觉得Select应该是：

.Select(g => new 
       { 
        ItemNumber = g.Key, 
        Column1 = (Int32?)g.Sum(p => p.Quantity) 
       }); 

注意，在第一线的变化匿名类型。分组的关键在于项目编号。

Answer 3

唯一的问题，我看到您的查询中

1. 缺少return声明按照意见
2. select语句应该是：

-

.Select(g => new { 
     ItemNumber = g.Key, 
     Total = g.Sum(p => p.Quantity) 
    }); 

---

编辑：如果你想要得到的，可以说ItemNumber和ITEMNAME，在生成的对象，还必须在组这些领域

db.WebsiteOrderStatus 
    .Where(x => x.AccountNumber == accountNumber && x.LastUpdatedStatus != 1) 
    .GroupBy(g => new { g.ItemNumber, g.ItemName }) 
    .Select(g => new 
       { 
        ItemNumber = g.Key.ItemNumber, 
        ItemName = g.Key.ItemName, 
        Count = g.Sum(item => item.Quantity) 
       }); 

Answer 4

public IQueryable<OrderStatus > lol(string accountNumber) 
{ 
    return db.WebsiteOrderStatus 
     .Where(x => x.AccountNumber == accountNumber && x.LastUpdatedStatus != 1) 
     .GroupBy(g => g.ItemNumber) 
     .Select(g => 
       new OrderStatus //This is your custom class, for binding only 
       { 
        ItemNumber = g.Key, 
        ItemName = g.First().ItemName, 
        Quantity = g.Sum(g => g.Quantity) 
       } 
     ); 
} 

Answer 5

您不能返回值的类型使用匿名类型。所以你永远不会编译代码。

另外你的linq表达式有IQueryable < [匿名类型]>结果类型。

我相信你可以做这样的事情：

public IQueryable<OrderStatus> lol(string accountNumber) 
{ 
    db.WebsiteOrderStatus 
     .Where(order => order.AccountNumber == accountNumber && order.LastUpdatedStatus != 1) 
     .GroupBy(order => order.ItemNumber) 
     .Select(grouping => new OrderStatus //This is your custom class, for binding only 
        { 
         ItemNumber = grouping.Key, 
         ItemName = grouping.First().ItemName, 
         Quantity = grouping.Sum(order => order.Quantity) 
        }); 
} 

I`ve固定我的答案太:)