XML Validation and XPath.

Question

Hi, I am having a problem using XPath when I validate Xml documents with a schema. Basically what happens is that an XPath query doesn't return the nodes I require if a schema is used to validate the XML. I'll try and explain it as briefly as possible here. Consider the following XML. Publisher Publisher When I execute the following code 2 nodes are returned by the XPath query and this output is produced in the debug pane; Count = 2 XML Book One XML Book Two XmlTextReader reader = new XmlTextReader(@"C:\books.xml"); XmlValidatingReader vreader = new XmlValidatingReader(reader); vreader.ValidationType = ValidationType.Schema; XPathDocument xmldoc = new System.Xml.XPath.XPathDocument(vreader); XPathNavigator nav = xmldoc.CreateNavigator(); nav.MoveToRoot(); nav.MoveToFirstChild(); XmlNamespaceManager nsMgr = new XmlNamespaceManager(nav.NameTable); nsMgr.AddNamespace( "ns" , nav.NamespaceURI ); XPathExpression xPathExpr = nav.Compile("//Publisher[. = 'Publisher']/parent::node()/Title"); xPathExpr.SetContext(nsMgr); XPathNodeIterator iterator = nav.Evaluate(xPathExpr) as XPathNodeIterator; System.Diagnostics.Debug.WriteLine("Count = " + iterator.Count.ToString()); while ( iterator.MoveNext() ) System.Diagnostics.Debug.WriteLine(iterator.Current.Value); However, if i validate the same Xml with a schema as illustrated below; Publisher Publisher The XML is validated by the schema without error but no nodes are returned by the XPath query. What is going wrong? Thanks.