如何在联接中使用L​​ambda表达式

Question

我是lambda exp的新手。我创建了一个linq语句，但是我不知道如何将我的代码转换为lambda exp。

var result = (from order1 in Orders
              join packedorder1 in VracExcluded on order1.codOrder equals packedorder1.codOrder
              join product1 in Products on order1.codProduct equals product1.codProduct
              join packedproduct1 in PackedProducts on packedorder1.codPackedProduct equals packedproduct1.codPackedProduct
              where order1.codOrder == _order.codOrder
              select new FinishedProductPrintingM
                            {
                                OF = order1.codOrder,
                                Item = "0",
                                Ligne = packedorder1.codLine,
                                Material = packedorder1.codPackedProduct,
                                Produit = product1.codProductType,
                                MaterialDescription = packedproduct1.lblPackedProduct,
                                Lot = packedorder1.codPackedBatch,
                                RéférenceClient = product1.codCustomerColor,
                                Quantité = packedorder1.nbrPackedQuantity.ToString(),
                                Déjàimprimé = packedorder1.nbrLabelPrinted
                            }).ToList();

任何人都可以帮助我理解我如何创建linq查询的lambda exp？

Answer 1

如果您不知道如何使用.net API，则使用msdn总是有用的。

var result = Orders.Join(VracExcluded, o => o.codOrder, v => v. codOrder, (o, v) => new { Order = o, VracExcluded = v })
                               .Join(Products, x => x.Order.codProduct, p => p.codProduct, (x, p) => new { Order = x.Order, VracExcluded = x.VracExcluded, Product = p })
                               .Join(PackedProducts, x => x.VracExcluded.codPackedProduct, pp => pp.codPackedProduct, (x, pp) => new { Order = x.Order, VracExcluded = x.VracExcluded, Product = x.Product, PackedProduct = pp })
                               .Where(x => x.Order.codOrder == _order.codOrder)
                               .Select(x => new FinishedProductPrintingM
                                   {
                                       OF = x.Order.codOrder,
                                       Item = "0",
                                       Ligne = x.VracExcluded.codLine,
                                       Material = x.VracExcluded.codPackedProduct,
                                       Produit = x.Product.codProductType,
                                       MaterialDescription = x.PackedProduct.lblPackedProduct,
                                       Lot = x.VracExcluded.codPackedBatch,
                                       RéférenceClient = x.Product.codCustomerColor,
                                       Quantité = x.VracExcluded.nbrPackedQuantity.ToString(),
                                       Déjàimprimé = x.VracExcluded.nbrLabelPrinted
                               })
                               .ToList();