Question

我正在为我的项目使用View / Presenter结构。该项目是一个包含OrderedItems和Products的电子通信站点。当调用 GetOrdersItemsByOrderID（orderID）时，我收到LINQ错误。

LINQ to Entities无法识别方法'DAL.Views.ProductView GetProductBySku（System.String）'方法，而且此方法无法转换为商店表达式。

我知道LINQ不喜欢其查询中的dynaimc内容，因此proplem是SELECT 产品= Presenters.ProductsPresenter.GetProductBySku（c.productSKU）

我不知道如何构建GetOrdersItemsByOrderID TOLIST，同时还有另一个GetProductBySku方法填充字段ProductDetail

/ ---------------- /

public static List<OrderItemsView> GetOrdersItemsByOrderID(int orderID)
{
    using (var ctx = new ProductEntities())
{

    var result = ctx.OrderedItems.Where(o => o.orderID == orderID)
        .Select(c => new OrderedItemsView
                         {
                             OrderItemID = c.orderItemID,
                             OrderID = c.orderID,
                             ProductSku = c.productSKU,
                             ProductPrice = c.productPrice,
                             ProdQuantity = c.prodQuantity,
                             ProductDetail = Presenters.ProductsPresenter.GetProductBySku(c.productSKU)
                         }).ToList();
    return result;
    }
}

/ ---------------- /

public class OrderedItemsView
    {
        public int OrderItemID { get; set; }
        public int OrderID { get; set; }
        public string ProductSku { get; set; }
        public decimal ProductPrice { get; set; }
        public int ProdQuantity { get; set; }
        public decimal? ProductWeight { get; set; }

      public ProductView ProductDetail { get; set; } <-- Get Product Details
    }

/ ---------------- /

public static Views.ProductView GetProductBySku(string sku)
    {
    using (GroupProductEntities ctx = new GroupProductEntities())
    {
        //-------------------------------------------------------------------//
        var results =
            ctx.Products.Where(p => p.clientID == Config.ClientID && p.productSKU == sku)
            .Select(p => new Views.ProductView
                             {
                                 ProductID = p.productID,
                                 ClientID = p.clientID,
                                 CategoryID = p.categoryID,
                                 ProductName = p.productName,
                                 ProductImage1 = p.productImage1,
                                 ProductPrice = p.productPrice,
                                 ProductInventory = p.productInventory,
                                 ProductSku = p.productSKU,
                             }).FirstOrDefault();
        return results;
    }
 }

/ ---------------- /

public class ProductView
{
    public int ProductID { get; set; }
    public int? CategoryID { get; set; }
    public string ProductName { get; set; }
    public string ProductShortDesc { get; set; }
    public string ProductImage1 { get; set; }
    public decimal? ProductPrice { get; set; }
    public decimal? ProductInventory { get; set; }
    public string ProductSku { get; set; }
}

/ ---------------- /

Answer 1

您可以通过添加＆＃34; ToList＆＃34;在调用该方法之前执行查询。

试试这个：

   var result = ctx.OrderedItems.Where(o => o.orderID == orderID).ToList()
        .Select(c => new OrderedItemsView
                         {
                             OrderItemID = c.orderItemID,
                             OrderID = c.orderID,
                             ProductSku = c.productSKU,
                             ProductPrice = c.productPrice,
                             ProdQuantity = c.prodQuantity,
                             ProductDetail = Presenters.ProductsPresenter.GetProductBySku(c.productSKU)
                         });

我将ToList()向上移了一下。您可能仍然需要在Select的末尾添加一个。

Linq选择内部方法错误 - LINQ to Entities无法识别该方法

1 个答案: