Question

What is the story behind XPath and support for namespaces? Did XPath as a specification precede namespaces? If I have a document where elements have been given a default namespace:

<foo xmlns='uri' /> 

It appears as though some of the XPath processor libraries won’t recognize //foo because of the namespace whereas others will. The option my team has thought about is to add a namespace prefix using regular expressions to the XPath (you can add a namespace prefix via XmlNameTable) but this seems brittle since XPath is such a flexible language when it comes to node tests.

Is there a standard that applies to this?

My approach is a bit hackish but it seems to work fine; I remove the xmlns declaration with a search/replace and then apply XPath.

string readyForXpath = Regex.Replace(xmldocument, 'xmlns=\'.+\'', String.Empty ); 

Is that a fair approach or has anyone solved this differently?

Answer 1

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