Linq 使用 select new 中的值来计算另一个字段

Question

是否可以在 linq 中执行以下操作，在我的 select new 中我使用 TotalOrderItems 中的值作为 TotalInStockItems 计算的一部分？

var Order = (from o in orderItems
             select new ShippingOrder { OrderId = orderItems.OrderId
                                        TotalOrderItems = orderItems.GroupBy(x => x.Sku).Count(),
                                        TotalInStockItems = TotalOrderItems - orderItems.Where(x => x.InStock =='F').GroupBy(x => x.Sku).Count(),
                                       }).ToList();

Answer 1

尝试使用let clause (C# Reference)存储该值以供稍后在查询中使用

(from o in orderItems
 let totalOrderItems = orderItems.GroupBy(x => x.Sku).Count()
 select new ShippingOrder { 
     OrderId = o.OrderId
     TotalOrderItems = totalOrderItems,
     TotalInStockItems = totalOrderItems - orderItems.Where(x => x.InStock =='F').GroupBy(x => x.Sku).Count(),
 }).ToList();