在XML属性ID中查找字符串的一部分，并在C＃中替换部分

Question

I've the following simple XML document:

<?xml version="1.0" encoding="utf-8"?>
<map title="enter map title here" id="_6cb8995f-430f-4422-918b-3042f6eda092">
  <topicref navtitle="Source" format="dita" id="_c2a73e14-2bbc-4730-88dc-0c4c699bd66e" scope="local" href="urn:ditastudio:topicreference:a2cec9de-d8e4-413e-ab1e-165a70c68adc">
    <topicref navtitle="Reference" format="dita" id="_18a0b17b-e5f0-4314-8536-d8152399f8d6" scope="local" href="urn:ditastudio:topicreference:7d25c6cc-b195-4968-af91-cd0d269f803b" />
  </topicref>
</map>

I want to use XPath to change part of the href in map//topicref/@href" . I want to keep the urn:ditastudio:topicreference: part and replace everything after it with with a random string.

How do I do this in C#?

So far this is what I'm doing....

foreach (Object map in mapList)
{
  XmlDocument theMap = new XmlDocument();
  theMap.XmlResolver = null;
  theMap.Load(map.ToString());

  String hrefPreText = "urn:ditastudio:topicreference:";
  String xPath = "/map//topicref/@href";


  foreach (string oldKey in OldToNewID_Dict.Keys)
  {
    String newVal = OldToNewID_Dict[oldKey];
    String newID = hrefPreText + newVal;

    XmlNode node = theMap.SelectSingleNode(xPath);
    node.Attributes[0].Value = newID;

    theMap.Save(map.ToString());
  }
}

I can't get my head around it. Any help would be appriciated!

Answer 1

Assuming you only want to do this for map/topicref , and not map/topicref/topicref too (in which case use : XElement.Descendants("topicref") ):

using System.Xml.XPath;
using System.Xml.Linq;

var xdocString = @"<?xml version="1.0" encoding="utf-8"?>
                    <map title="enter map title here" id="_6cb8995f-430f-4422-918b-3042f6eda092">
                      <topicref navtitle="Source" format="dita" id="_c2a73e14-2bbc-4730-88dc-0c4c699bd66e" scope="local" href="urn:ditastudio:topicreference:a2cec9de-d8e4-413e-ab1e-165a70c68adc">
                        <topicref navtitle="Reference" format="dita" id="_18a0b17b-e5f0-4314-8536-d8152399f8d6" scope="local" href="urn:ditastudio:topicreference:7d25c6cc-b195-4968-af91-cd0d269f803b" />
                      </topicref>
                    </map>";

XDocument xdoc = XDocument.Parse(xdocString);
String hrefPreText = "urn:ditastudio:topicreference:";

foreach (var topicref in xdoc.XPathSelectElements("map/topicref"))
{
    topicref.Attribute("href").Value = hrefPreText + "something random";
}

If you want to try this code, make sure to escape the " (replace with "" ) in xdocString , it messed up the formatting if I did it here.