Read in an XML String with Namespaces for Use in an XSL Transformation

Question

In an ASP.NET 2.0 website, I have a string representing some well-formed XML. I am currently creating an XmlDocument object with it and running an XSL transformation for display in a Web form. Everything was operating fine until the XML input started to contain namespaces.

How can I read in this string and allow namespaces?

I've included the current code below. The string source comes from an HTML encoded node in a WordPress RSS feed.

XPathNavigator myNav= myPost.CreateNavigator();
XmlNamespaceManager myManager = new XmlNamespaceManager(myNav.NameTable);
myManager.AddNamespace("content", "http://purl.org/rss/1.0/modules/content/");
string myPost = HttpUtility.HtmlDecode("<post>" +
    myNav.SelectSingleNode("//item[1]/content:encoded", myManager).InnerXml +
    "</post>");
XmlDocument myDocument = new XmlDocument();
myDocument.LoadXml(myPost.ToString());

The error is on the last line:

"System.Xml.XmlException: 'w' is an undeclared namespace. Line 12, position 201. at System.Xml.XmlTextReaderImpl.Throw(Exception e) ..."

Answer 1

Your code looks right.

The problem is probably in the xml document you're trying to load. It must have elements with a "w" prefix, without having that prefix declared in the XML document

For example, you should have:

<test xmlns:w="http://..."&gt;
  <w:elementInWNamespace />
</test>

(your document is probably missing the xmlns:w="http://")

Answer 2

Gut feel - one of the namespaces declared in //content:encoding is being dropped (probably because you're using the literal .InnerXml property)

What's 'w' namespace evaluate to in the myNav DOM? You'll want to add xmlns:w= to your post node. There will probably be others too.