XPATHS and Default Namespaces

You need local-name():

http://www.w3.org/TR/xpath#function-local-name

To crib from http://web.archive.org/web/20100810142303/http://jcooney.net:80/archive/2005/08/09/6517.aspx:

<foo xmlns='urn:foo'>
  <bar>
    <asdf/>
  </bar>            
</foo>

This expression will match the “bar” element:

  //*[local-name()='bar']

This one won't:

 //bar

I tried something similar to what palehorse proposed and could not get it to work. Since I was getting data from a published service I couldn't change the xml. I ended up using XmlDocument and XmlNamespaceManager like so:

XmlDocument doc = new XmlDocument();
doc.LoadXml(xmlWithBogusNamespace);            
XmlNamespaceManager nSpace = new XmlNamespaceManager(doc.NameTable);
nSpace.AddNamespace("myNs", "http://theirUri");

XmlNodeList nodes = doc.SelectNodes("//myNs:NodesIWant",nSpace);
//etc

The issue is that an element without a namespace is declared to be in the NULL namespace - therefore if //foo matched against the namespace you consider to be the 'default' there would be no way to refer to an element in the null namespace.

Remember as well that the prefix for a namespace is only a shorthand convention, the real element name (Qualified Name, or QName for short) consists of the full namespace and the local name. Changing the prefix for a namespace does not change the 'identity' of an element - if it is in the same namespace and same local name then it is the same kind of element, even if the prefix is different.

XPath 2.0 (or rather XSLT 2.0) has the concept of the 'default xpath namespace'. You can set the xpath-default-namespace attribute on the xsl:stylesheet element.

XPATHS and Default Namespaces

Related

Recent Posts