List<T> 重复记录合并 数量相加
实体类如下

C# code

public partial class ProductItem    {        /// <summary>        /// 订单编号        /// </summary>        public string orderId { get; set; }        /// <summary>        /// 条形码        /// </summary>        public string barCode { get; set; }        /// <summary>        /// 产品名称        /// </summary>        public string Title { get; set; }        /// <summary>        /// 单价        /// </summary>        public string Price { get; set; }        /// <summary>        /// 订货数量        /// </summary>        public string quantity { get; set; }        /// <summary>        /// 规格        /// </summary>        public string Spec { get; set; }        /// <summary>        /// 优惠价        /// </summary>        public double preferPrice { get; set; }        /// <summary>        /// 原价        /// </summary>        public double costPrice { get; set; }        /// <summary>        /// 审核备注        /// </summary>        public string auditMemo { get; set; }    }

需要在这里判断如果barCode 条形码相同的情况下合并为一个商品quantity 订货数量相加

C# code

List<Model.ProductItem> listProductItem = new List<Model.ProductItem>();List<Model.SellOrderCart> listOrderCart = SellOrderCart.GetModelList(OrderID);foreach (Model.SellOrderCart item in listOrderCart){                        Model.ProductItem modelProductItem = new Model.ProductItem();                        modelProductItem.orderId = item.OrderID.ToString();                        modelProductItem.barCode = SellOrder.GetSpec(item.Title, item.ItemCode, item.GoodsTypeID, item.GoodsID, item.Specs, "", item.YGD);                        modelProductItem.Title = SellOrder.GetTitle(item.Title, item.SetTableID);                        modelProductItem.Price = item.SalePrice.ToString();                        modelProductItem.quantity = item.Quantity.ToString();                        modelProductItem.Spec = modelProductItem.barCode;                        modelProductItem.preferPrice = Convert.ToDouble(item.SalePrice);                        modelProductItem.costPrice = Convert.ToDouble(item.SalePrice);                        modelProductItem.auditMemo = SellOrder.GetAuditMemo(item.UserRemark, item.YGD);                        //如何判断barCode 条形码相同的情况下合并为一个商品quantity 订货数量相加                        listProductItem.Add(modelProductItem);}

[解决办法]
代码仅供参考:

C# code

            Dictionary<string, Model.ProductItem> productDic = new Dictionary<string, Model.ProductItem>();            List<Model.SellOrderCart> listOrderCart = SellOrderCart.GetModelList(OrderID);            foreach (Model.SellOrderCart item in listOrderCart)            {                string barCode = SellOrder.GetSpec(item.Title, item.ItemCode, item.GoodsTypeID, item.GoodsID, item.Specs, "", item.YGD);                if (productDic.ContainsKey(barCode))                {                    productDic[barCode].quantity += item.Quantity.ToString();                }                else                {                    Model.ProductItem modelProductItem = new Model.ProductItem();                    modelProductItem.orderId = item.OrderID.ToString();                    modelProductItem.barCode = barCode;                    modelProductItem.Title = SellOrder.GetTitle(item.Title, item.SetTableID);                    modelProductItem.Price = item.SalePrice.ToString();                    modelProductItem.quantity = item.Quantity.ToString();                    modelProductItem.Spec = modelProductItem.barCode;                    modelProductItem.preferPrice = Convert.ToDouble(item.SalePrice);                    modelProductItem.costPrice = Convert.ToDouble(item.SalePrice);                    modelProductItem.auditMemo = SellOrder.GetAuditMemo(item.UserRemark, item.YGD);                    productDic.Add(barCode, modelProductItem);                }            } 
 
[解决办法]
探讨

实体类如下
C# code

public partial class ProductItem
    {
        /// <summary>
        /// 订单编号
        /// </summary>
        public string orderId { get; set; }
        /// <summary>
        /// 条形码
……

[解决办法]

           List<ProductItem> p = new List<ProductItem>();
           p.Add(new ProductItem() { orderId = "1", barCode = "1", quantity = "2" });
           p.Add(new ProductItem() { orderId = "2", barCode = "1", quantity = "3" });
           p.Add(new ProductItem() { orderId = "3", barCode = "3", quantity = "2" });
           p.Add(new ProductItem() { orderId = "4", barCode = "4", quantity = "3" });
           var query = from t in p
                                      group t by t.barCode into g
                                      select g.Take(1).Select(c => new ProductItem()
                                      {
                                          orderId = c.orderId,
                                          barCode = c.barCode,
                                          Spec = c.Spec,
                                          Title = c.Title,
                                          auditMemo = c.auditMemo,
                                          costPrice = c.costPrice,
                                          preferPrice = c.preferPrice,
                                          Price = c.Price,
                                          quantity = p.Where(d => d.barCode == c.barCode).Select(ee => int.Parse(ee.quantity)).Sum().ToString()
                                      });
           List<ProductItem> reval = new List<ProductItem>();
           foreach (var r in query)  
           {
               reval.Add(r.First());
           }
[解决办法]
C# code
 var vardt = from p in modelProductItem group p by new {p.orderId ,p.barCode} into g let sum = g.Sum(x => int.Parse(x.quantity)) select new { orderId= g.Key,//这里只写了两个字段，其他字段自己加上就行了 Sum = sum };