Question

我正在使用.NET 4数据可视化图表并使用Linq查询来获取图表的数据。我是Linq的新手，所以不确定如何说出这个查询。这是它的作用，我有以下表格从

中提取数据

订单
ShipmentSchedule

订单表包含已订购的产品，OrderId，已发货的金额以及该订单的剩余数量。一个订单只能包含一个产品。我想在OrderShipment类中获得所有Ordershipments，制作一个List＆lt;＆gt;对于它并按每个产品分组，并显示订购的每个产品和已发货的总数量。下面的查询总结了所有订单的发货数量，这是正确的，但由于它正在制作OrderShipments列表，我想要所有货件中每个订单的剩余数量，并按产品加总。现在它将所有货物的剩余数量加起来是错误的，因为订单在所有货件中具有相同的剩余数量。如何获得每个产品的剩余数量，以便查询正确地按每个订单累计剩余数量？如果您有建议，请提供代码如何完成此操作的示例，您的帮助非常感谢，谢谢

 private class ChartDataPoint
    {
        public string ProductName { get; set; }
        public double QtyRemaining { get; set; }
        public double QtyShipped { get; set; }
    }

    private class OrderShipment
    {
        public string ProductName { get; set; }
        public double QuantityRemaining { get; set; }
        public double QuantityShipped { get; set; }
        public int OrderId { get; set; }
    }


      List<OrderShipment> productsOrdered =
          (from os in Statistics.OptimalShipments
           from o in Statistics.OrdersPlaced
           where ((os.Date >= Statistics.ShippingWindowStartDate) &&
                   (os.Date <= Statistics.ShippingWindowEndDate) &&
                   (os.OrderId == o.OrderId) &&
                  ((o.ClientLocationId == ClientLocation.ClientLocationId)))
           select new OrderShipment()
           {
               ProductName = o.Product.Name,
               QuantityRemaining = o.RemainingQuantity,
               QuantityShipped = os.QuantityShipped,

           }).ToList();

        var query = productsOrdered.GroupBy(p => p.ProductName);
        List<ChartDataPoint> chartDataPoints = new List<ChartDataPoint>();
        foreach (var productGroup in query)
        {
            chartDataPoints.Add(new ChartDataPoint()
            {
               ProductName = productGroup.Key,

               // This is obv wrong this sums up the Remaining quantity across   
               // all shipments for a order when we should be only taking the 
               //Remaining quantity once for each order across all shipments.
               QtyRemaining = productGroup.Sum(po => po.QuantityRemaining),
               QtyShipped = productGroup.Sum(po => po.QuantityShipped)
            });
        }

Answer 1

据我了解，您的productGroup应该有很多按照产品名称分组的OrderShipment个对象。那么你想要总和QuantityShipped和QuantityRemaining应该都是相同的，你想只取这个值？

如果是这样，那么你应该这样做：

QtyRemaining = productGroup.First();

如果我误解了你可能想简化解释，可能还有一个例子......

Linq查询需要正确的总和

1 个答案: