Question

I’m having problems selecting nodes with XPath. I’ll show the example, xml file is shortened due to the extensive amount of data in the real one:

This is the subset of the XML:

<?xml version="1.0" encoding="ISO-8859-1"?>
<design xmlns="namespace_hidden" createddate="2012-12-07" createdby="User" name="New   Design">
  ...
  <variables>
  <measurements>
    <measurement name="Measurement001">
      <sample name="1">
        <position>[0,0]</position>
        <variables>
          <qualitative name="bId">
            <class>2193</class>
          </qualitative>
        </variables>
      </sample>
      ...
      <sample name="4">
        <position>[3,0]</position>
        <variables>
          <qualitative name="Q2">
            <class>V0</class>
          </qualitative>
          <qualitative name="Q3">
            <class>V2</class>
          </qualitative>
          <qualitative name="Q4">
            <class>V1</class>
          </qualitative>
          <quantitative name="Q5">
            <unit>Percent</unit>
            <value>8</value>
          </quantitative>
        </variables>
      </sample>
    </measurement>
    <measurement name="Measurement002">
        ..
    </measurement>
    ...
   </measurements>
</design>

Now, im trying to select all variables under a specific sample, under a specific measurement.

This is the querying method I use:

// Creating the navigator
var doc = new XPathDocument(xmlDoc[0]);
var navigator = doc.CreateNavigator();

// Creating the namespace manager:
XmlNamespaceManager nsMan = null;
if (navigator.NameTable != null) {
     nsMan = new XmlNamespaceManager(navigator.NameTable);
     nsMan.AddNamespace("y", xmlNs);
     nsMan.PushScope();
}

// Executing the query
var iterator = navigator.Select(string.Format("/y:design/y:measurements/y:measurement[name='{0}']/y:sample[name={1}]/y:variables/y:qualitative", currentMeasurement.Name, currentSample.Name), nsMan);

When I use this query I get the first measurement and the first sample, so that works:

string.Format("/y:design/y:measurements/y:measurement[1]/y:sample[1]"

but if I use this query:

"/y:design/y:measurements/y:measurement[name='Measurement001']/y:sample[1]"

I dont get any results

In desperation I have also tried different combinations of ” around the attribute values to no success.

What am I doing wrong?

Best regards, and thanks for any help!
Richard

Answer 1

Use an at sign @ to access attributes:

/y:design/y:measurements/y:measurement[@name='Measurement001']/y:sample[1]
                                       ^