使用 XPath 按 Id 选择 XMLNode [英] Select XMLNode by Id using XPath

问题描述

我有以下 XML 片段，请注意 Reference 节点包含一个链接到 Body 节点的 Id 属性的 URI.

I have the below fragement of XML, notice that the Reference node holds a URI which links to the Id attribute of the Body node.

 <Reference URI="#Body">
  <SOAP-ENV:Body Id="Body" xmlns:SOAP-ENV="http://www.dingo.org">
    <ns0:Add xmlns:ns0="http://www.moo.com">
      <ns0:a>2</ns0:a>
      <ns0:b>3</ns0:b>
    </ns0:Add>
  </SOAP-ENV:Body>

如果我有 URI 属性的值，我将如何获得整个 Body XMLNode?我认为这最好通过 XPath 表达来完成，但对 XPath 没有任何线索.请注意，XML 并不总是那么简单.我在 c# 中这样做 顺便说一句 :)

If I had the value of the URI attribute how would I then get the whole Body XMLNode? I presume this would be best done via an XPath epression but haven't any clue on XPath. Note that the XML will not always be so simple. I'm doing this in c# btw :)

有什么想法吗?

谢谢

乔恩

我事先不知道 XML 结构或命名空间，我只知道引用元素具有我想要检索的 xmlNode 的 ID，希望这能更清楚一些.

I wouldn't know the XML structure or namespaces before hand, all I would know is that the reference element has the ID of the xmlNode i want to retrieve, hope this is sligtly clearer.

推荐答案

您可以向 XPath 表达式的任何步骤添加适用于相对(或绝对节点)的条件.

You can add a condition that applies to a relative (or absolute node) to any step of an XPath expression.

在这种情况下:

//*[@id=substring-after(/Reference/@URI, '#')]

//* 匹配文档中的所有元素.[] 中的部分是条件.在条件内部，采用根 References 节点的 URI 元素部分，但忽略#"(以及它之前的任何内容).

The //* matches all elements in the document. The part in [] is a condition. Inside the condition the part of the URI element of the root References node is taken, but ignoring the '#' (and anything before it).

示例代码，假设您已将 XML 加载到 XPathDocument doc:

Sample code, assuming you have loaded your XML into XPathDocument doc:

var nav = doc.CreateNavigator();
var found = nav.SelectSingleNode("//*[@id=substring-after(/Reference/@URI, '#')]");

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