Find Specific XML Node value

[contissi]

I am currently trying to read in and parse an XML string that looks similar to:

<?xml version="1.0" encoding="UTF-8"?>
<test version="1.1">
  <query id="1234534567">
    <queryName>getHistory</queryName>
    <inputParameters>
      <parameter>
        <parameterName>requestorId</parameterName>
        <parameterValue>1111</parameterValue>
      </parameter>
      <parameter>
        <parameterName>employeeNumber</parameterName>
        <parameterValue>1111</parameterValue>
      </parameter>
      <parameter>
        <parameterName>IDNumber</parameterName>
        <parameterValue>123456</parameterValue>
      </parameter>
    </inputParameters>
  </query>
</test>

Seeing that I do not have unique node names, is it possible to grab a specific node value and return its counterpart. What I mean is, is there a way to look for the parameterName with a value of IDNumber and return its corresponding parameterValue? I have been unsuccessful thus far... Any help would be greatly appreciated.

[Talikag]

Yes - using XPATH you can search for specific nodes. I believe something like that would work:

XmlDocument doc;
//load your document to doc here...
XmlNode node = doc.SelectSingleNode("test/query/inputParameters/" +
   "parameter[parameterValue/text() = IDNumber]/parameterValue");
Console.WriteLine(node.InnerText);

Your probably wonder what the XPATH query I wrote does.
Well, here's a translation of this XPath query to plain English:
-Look for an XML element named "test".
-Then look for a child of "test" named "query".
-Then look for a child of "query" named "inputParameters".
-Then look for a "parameter" child that has a "parameterValue" child, whose text is "IDNumber".
-Return the child named "parameterValue" of this parameter.

Note that if there can be more than one parameters with paramaterName = "IDNumber", you should use the Select method instead of SelectSingleNode.
SelectSingleNode will return the first node that matches your XPATH query, whereas Select will return a collection of all the nodes that match your XPATH query.

In general, if you work with XML files, you should get familiar with XPATH - it's very useful.

Tal.