本文介绍了VB.NET中的LINQ to XML总和子节点的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有来自Amazon Marketplace API的以下XML.我需要对所有商品的所有Item/ItemPrice/Component[type='Principal']/Amount值求和，以计算订单总额.在VB.NET中使用LINQ to XML可以做到这一点吗?
I have the following XML from Amazon's Marketplace API. I need to sum all the values of Item/ItemPrice/Component[type='Principal']/Amount for all Items to compute an order total. Is this possible to do using LINQ to XML in VB.NET?
<?xml version="1.0"?>
<AmazonEnvelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="amzn-envelope.xsd">
<Header>
<DocumentVersion>1.01</DocumentVersion>
<MerchantIdentifier>My Store</MerchantIdentifier>
</Header>
<MessageType>OrderReport</MessageType>
<Message>
<MessageID>1</MessageID>
<OrderReport>
<AmazonOrderID>050-1234567-1234567</AmazonOrderID>
<AmazonSessionID>902-1030835-1234567</AmazonSessionID>
<OrderDate>2002-05-01T15:20:15-08:00</OrderDate>
<OrderPostedDate>2002-05-01T15:21:49-08:00</OrderPostedDate>
<BillingData>
<BuyerEmailAddress>[email protected]</BuyerEmailAddress>
<BuyerName>Joe Smith</BuyerName>
<BuyerPhoneNumber>206-555-1234</BuyerPhoneNumber>
</BillingData>
<FulfillmentData>
<FulfillmentMethod>Ship</FulfillmentMethod>
<FulfillmentServiceLevel>Standard</FulfillmentServiceLevel>
<Address>
<Name>Joe Smith</Name>
<AddressFieldOne>1234 Main St.</AddressFieldOne>
<City>Seattle</City>
<StateOrRegion>Washington</StateOrRegion>
<PostalCode>98004</PostalCode>
<CountryCode>US</CountryCode>
<PhoneNumber>206-555-1234</PhoneNumber>
</Address>
</FulfillmentData>
<Item>
<AmazonOrderItemCode>12345678901234</AmazonOrderItemCode>
<SKU>1234</SKU>
<Title>Programming Perl, 3rd edition</Title>
<Quantity>1</Quantity>
<ProductTaxCode>1234</ProductTaxCode>
<ItemPrice>
<Component>
<Type>Principal</Type>
<Amount currency="USD">10.00</Amount>
</Component>
<Component>
<Type>Shipping</Type>
<Amount currency="USD">3.49</Amount>
</Component>
<Component>
<Type>Tax</Type>
<Amount currency="USD">1.29</Amount>
</Component>
<Component>
<Type>ShippingTax</Type>
<Amount currency="USD">0.24</Amount>
</Component>
</ItemPrice>
<ItemFees>
<Fee>
<Type>Commission</Type>
<Amount currency="USD">-0.75</Amount>
</Fee>
</ItemFees>
<ItemTaxData>
<TaxJurisdictions>
<TaxLocationCode>12345678</TaxLocationCode>
<City>Seattle</City>
<County>King</County>
<State>WA</State>
</TaxJurisdictions>
<TaxableAmounts>
<District currency="USD">10.00</District>
<City currency="USD">10.00</City>
<County currency="USD">0.00</County>
<State currency="USD">10.00</State>
</TaxableAmounts>
<NonTaxableAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">10.00</County>
<State currency="USD">0.00</State>
</NonTaxableAmounts>
<ZeroRatedAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">0.00</County>
<State currency="USD">0.00</State>
</ZeroRatedAmounts>
<TaxCollectedAmounts>
<District currency="USD">0.23</District>
<City currency="USD">0.53</City>
<County currency="USD">0.00</County>
<State currency="USD">0.53</State>
</TaxCollectedAmounts>
<TaxRates>
<District>0.0230</District>
<City>0.0530</City>
<County>0.0230</County>
<State>0.0530</State>
</TaxRates>
</ItemTaxData>
<ShippingTaxData>
<TaxJurisdictions>
<TaxLocationCode>12345678</TaxLocationCode>
<City>Seattle</City>
<County>King</County>
<State>WA</State>
</TaxJurisdictions>
<TaxableAmounts>
<District currency="USD">3.49</District>
<City currency="USD">3.49</City>
<County currency="USD">0.00</County>
<State currency="USD">3.49</State>
</TaxableAmounts>
<NonTaxableAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">3.49</County>
<State currency="USD">0.00</State>
</NonTaxableAmounts>
<ZeroRatedAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">0.00</County>
<State currency="USD">0.00</State>
</ZeroRatedAmounts>
<TaxCollectedAmounts>
<District currency="USD">0.04</District>
<City currency="USD">0.10</City>
<County currency="USD">0.00</County>
<State currency="USD">0.10</State>
</TaxCollectedAmounts>
<TaxRates>
<District>0.0120</District>
<City>0.0190</City>
<County>0.0190</County>
<State>0.0190</State>
</TaxRates>
</ShippingTaxData>
<Promotion>
<PromotionClaimCode>ABC123</PromotionClaimCode>
<MerchantPromotionID>12345678</MerchantPromotionID>
<Component>
<Type>Principal</Type>
<Amount currency="USD">-1.00</Amount>
</Component>
</Promotion>
</Item>
<Item>
<AmazonOrderItemCode>12345678901235</AmazonOrderItemCode>
<SKU>1234</SKU>
<Title>Programming ASP.NET, 2nd edition</Title>
<Quantity>1</Quantity>
<ProductTaxCode>1234</ProductTaxCode>
<ItemPrice>
<Component>
<Type>Principal</Type>
<Amount currency="USD">12.00</Amount>
</Component>
<Component>
<Type>Shipping</Type>
<Amount currency="USD">3.49</Amount>
</Component>
<Component>
<Type>Tax</Type>
<Amount currency="USD">1.42</Amount>
</Component>
<Component>
<Type>ShippingTax</Type>
<Amount currency="USD">0.24</Amount>
</Component>
</ItemPrice>
<ItemFees>
<Fee>
<Type>Commission</Type>
<Amount currency="USD">-0.75</Amount>
</Fee>
</ItemFees>
<ItemTaxData>
<TaxJurisdictions>
<TaxLocationCode>12345678</TaxLocationCode>
<City>Seattle</City>
<County>King</County>
<State>WA</State>
</TaxJurisdictions>
<TaxableAmounts>
<District currency="USD">10.00</District>
<City currency="USD">10.00</City>
<County currency="USD">0.00</County>
<State currency="USD">10.00</State>
</TaxableAmounts>
<NonTaxableAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">10.00</County>
<State currency="USD">0.00</State>
</NonTaxableAmounts>
<ZeroRatedAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">0.00</County>
<State currency="USD">0.00</State>
</ZeroRatedAmounts>
<TaxCollectedAmounts>
<District currency="USD">0.23</District>
<City currency="USD">0.53</City>
<County currency="USD">0.00</County>
<State currency="USD">0.53</State>
</TaxCollectedAmounts>
<TaxRates>
<District>0.0230</District>
<City>0.0530</City>
<County>0.0230</County>
<State>0.0530</State>
</TaxRates>
</ItemTaxData>
<ShippingTaxData>
<TaxJurisdictions>
<TaxLocationCode>12345678</TaxLocationCode>
<City>Seattle</City>
<County>King</County>
<State>WA</State>
</TaxJurisdictions>
<TaxableAmounts>
<District currency="USD">3.49</District>
<City currency="USD">3.49</City>
<County currency="USD">0.00</County>
<State currency="USD">3.49</State>
</TaxableAmounts>
<NonTaxableAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">3.49</County>
<State currency="USD">0.00</State>
</NonTaxableAmounts>
<ZeroRatedAmounts>
<District currency="USD">0.00</District>
<City currency="USD">0.00</City>
<County currency="USD">0.00</County>
<State currency="USD">0.00</State>
</ZeroRatedAmounts>
<TaxCollectedAmounts>
<District currency="USD">0.04</District>
<City currency="USD">0.10</City>
<County currency="USD">0.00</County>
<State currency="USD">0.10</State>
</TaxCollectedAmounts>
<TaxRates>
<District>0.0120</District>
<City>0.0190</City>
<County>0.0190</County>
<State>0.0190</State>
</TaxRates>
</ShippingTaxData>
<Promotion>
<PromotionClaimCode>ABC123</PromotionClaimCode>
<MerchantPromotionID>12345678</MerchantPromotionID>
<Component>
<Type>Principal</Type>
<Amount currency="USD">-1.00</Amount>
</Component>
</Promotion>
</Item>
</OrderReport>
</Message>
</AmazonEnvelope>
推荐答案
这是在VB中使用具有Linq语法的更多idomatic inline-XML解决此问题的方法.
This is how you'd solve this in VB using the more idomatic inline-XML with Linq syntax.
Dim result =
From xcmp In azm...<Item>.<ItemPrice>.<Component>
Where xcmp.<Type>.Value = "Principal"
Select Convert.ToDecimal(xcmp.<Amount>.Value)
Console.WriteLine(result.Sum().ToString())
三点语法用于子代搜索.单点语法移至子节点. azm变量是保存您的XML的XDocument.
The triple dot syntax is for descendant searches. The single dot syntax moves to the child node. The azm variable is an XDocument holding your XML.
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