Question

Is it possible to add/use custom functions inside .Net XPath evaluator? For example, I’d like to do a search with regex, which xPath 1.0 does not support. Can I add something similar to

bool RegexSearch(string regex, string text)

and register it with something similar to

xPathNavigator.RegisterFunction("regex-search",RegexSearch);

so I can use it inside my xPath queries?

Answer 1

Yes, you will need to inherit from System.Xml.Xsl.XsltContext. Please check this link for details of the implementation.

Using ms: xpath functions inside XPathExpression

MSDN – Adding Custom Functions to XPath

Microsoft KB Article, the original link on MS is dead. But I manage to find an alternate –
HOW TO: Implement and Use Custom Extension Functions When You Execute XPath Queries in Visual C# .NET.