Reference to undeclared namespace prefix when parsing MSXML

Question

How do I solve the

Reference to undeclared namespace prefix: \'%s\'

problem with Microsoft\'s msxml implementation?

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I\'m using a

Answer 1

If you are using XMLSerializer and see this error, it is likely that you are running into the IE bug described here:

https://stackoverflow.com/a/11399681

It took me a lot of time to realize that this was happening, so I thought it best to link these two issues.

Answer 2

doc.setProperty('SelectionNamespaces', 'xmlns:rss="http://purl.org/rss/1.0/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:cb="http://www.cbwiki.net/wiki/index.php/Specification_1.1"');

Dont forget to load the xsd file or schema to the xmldoc object

is the way to go

I dont have enough reputation to comment. But that bit there saved me a lot of time.

Thank you so much

Answer 3

Using SelectionNamespaces is the correct approach, you are just missing a namespace.

Notice that your XML document explicitly sets the default namespace as follows:

xmlns="http://purl.org/rss/1.0/"

This means that any element without a prefix, such as the item element, is actually in the default namespace. So if you want to select that element with an XPath expression, you must first set an appropriate selection namespace.

To do this, you can change your call to setProperty like so:

doc.setProperty('SelectionNamespaces', 'xmlns:rss="http://purl.org/rss/1.0/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:cb="http://www.cbwiki.net/wiki/index.php/Specification_1.1"');

Here you've assigned the default namespace from the document to the rss: prefix in your XPath expression. With that change in place, the following XPath expression should work correctly:

nodes = doc.selectNodes('/rdf:RDF/rss:item/cb:statistics/cb:exchangeRate/cb:targetCurrency');

It works because it references the item element using the correct namespace. The fact that the prefix differs between the XPath expression and the original document is immaterial. It is the namespace which the prefix is bound to that matters.