根据其他值从 XML 文档中选择某些值

Question

我有以下 XML，

<OrderReport>
  <Item>
    <Promotion>      
      <Component>
        <Type>Principal</Type>
        <Amount currency="USD">-0.25</Amount>
      </Component>
      <Component>
        <Type>Shipping</Type>
        <Amount currency="USD">0.00</Amount>
      </Component>
    </Promotion>
  </Item>
</OrderReport>

我需要获取每种类型的金额。以下是我正在尝试的内容

var q = from orders in xDoc.Descendants("OrderReport")    
        select new 
        {
            //This should return me the Principal Amount
            ItemDiscountAmount = orders.Element("Item")
                                       .Element("Promotion")
                                       .Element("Component")
                                       .Element("Amount")
                                       .Value,
            //This should return me the Principal Currency
            ItemDiscountCurrency = orders.Element("Item")
                                         .Element("Promotion")
                                         .Element("Component")
                                         .Element("Amount")
                                         .Attribute("currency")
                                         .Value,

            //This should return me the Shipping Amount
            ShipDiscountAmount = orders.Element("Item")
                                       .Element("Promotion")
                                       .Element("Component")
                                       .Element("Amount")
                                       .Value,
            //This should return me the Shipping Currency                        
            ShipDiscountCurrency = orders.Element("Item")
                                         .Element("Promotion")
                                         .Element("Component")
                                         .Element("Amount")
                                         .Attribute("currency")
                                         .Value,
        };

我编写​​的代码不正确。它现在返回我所有财产的本金和货币。这些注释描述了出于理解目的应返回的内容。 该查询基本上应该根据 节点下的 节点返回价格和货币。不知道如何在这种情况下提出条件。

Answer 1

如果您首先找到包含 Principal 类型或 Shipping 类型的元素，然后获取所需的值，将会有所帮助。我相信这就是你所追求的。

// using an XPATH will make this nicer to express
var query = from report in xDoc.Descendants("OrderReport")
            let principalAmount = report.XPathSelectElement("./*/*/Component[Type='Principal']/Amount")
            let shippingAmount = report.XPathSelectElement("./*/*/Component[Type='Shipping']/Amount")
            select new
            {
                ItemDiscountAmount = (decimal)principalAmount,
                ItemDiscountCurrency = (string)principalAmount.Attribute("currency"),
                ShipDiscountAmount = (decimal)shippingAmount,
                ShipDiscountCurrency = (string)shippingAmount.Attribute("currency"),
            };

只需记住包含命名空间 System.Xml.XPath 即可使其正常工作。

Answer 2

你只需要添加Where子句，

var q = from orders in xdoc1.Descendants("OrderReport")
        join ItemPrices in xdoc1.Descendants 
        where orders.Component.Type == "Principal"
        select new 
        {
            OrderId = orders.Element("OrderID"),
            City = orders.Element("City"),
            CountryRegion = orders.Element("CountryCode"),
            State = orders.Element("StateOrRegion"),
            Street1 = orders.Element("AddressFieldOne"),
            Telephone = orders.Element("PhoneNumber"),
            ZipCode = orders.Element("PostalCode"),
            Name = orders.Element("Name"),
            OrderDate = orders.Element("OrderDate"),
            ShipMethod = orders.Element("FulfillmentMethod"),
            ItemCode = orders.Element("AmazonOrderItemCode"),
            SKU = orders.Element("SKU"),
            QtyOrdered = orders.Element(""),
            ItemTaxAmount = orders.Element(""),
            ItemTaxCurrency = orders.Element(""),
            ItemShipTaxAmount = orders.Element(""),
            ItemShipTaxCurrency = orders.Element(""),
            ItemTotalAmount = orders.Element(""),
            ItemTotalCurrency = orders.Element(""),
            ItemUnitPrice = orders.Element(""),
            ItemCommissionAmount = orders.Element(""),
            ItemCommissionCurrency = orders.Element("")
         };