如何读取XML数据

Question

我有XML字符串,我试图用代码阅读

XmlDocument xmlDoc = new XmlDocument();
xmlDoc.LoadXml(XMLString);
XmlNode node = xmlDoc.SelectSingleNode("//cart/cart-item/url/text()");
Console.WriteLine(node.Value);  

但node总是空的.任何人都可以解释什么是错的？

<order xmlns="http://ws.plimus.com">
<order-id>8301446</order-id>
<ordering-shopper>
<shopper-id>25879327</shopper-id>
</ordering-shopper>
<cart>
<charged-currency>USD</charged-currency>
<cart-item>
<sku>...</sku>
<quantity>1</quantity>
<url>
https://ws.plimus.com:443/services/2/subscriptions/9433117
</url>
<item-sub-total>9.00</item-sub-total>
</cart-item>
<tax>0.00</tax>
<tax-rate>0</tax-rate>
<total-cart-cost>9.00</total-cart-cost>
</cart>
</order>

Answer 1

默认情况下,XPath将未加前缀的名称视为"无名称空间".您应该使用XmlNamespaceManager解析xmlns

XmlDocument xmlDoc = new XmlDocument();
XmlNamespaceManager nm = new XmlNamespaceManager(xmlDoc.NameTable);

nm.AddNamespace("ns", "http://ws.plimus.com");
xmlDoc.LoadXml(xmlString);
XmlNode node = xmlDoc.SelectSingleNode("//ns:cart/ns:cart-item/ns:url/text()", nm);

Console.WriteLine(node.Value);  

编辑:如果您有可能将xml根元素更改为

<order xmlns:ns="http://ws.plimus.com">

那么你不需要每次都在XPath中指定'ns',它看起来像//cart/cart-item/url/text().

XmlNamespaceManager 无论如何都需要如示例所示的配置