converting an XMLDocument to an XPathDocument

[Kai77]

Hi,

I am tryin to navigate through an XMLDocument using XPathNavigator. PagesXML is a valid xmldocument and i am trying to assign it to xpathDoc by casting it. But I am getting a 'Specified cast is invalid' message. How can I navigate through the XML?

Dim getSurveyPagesXML As New getSurveyXML
Dim PagesXML As XmlDocument = getSurveyPagesXML.getXML(strFolder, "pages")

Dim xpathDoc As XPathDocument
Dim xmlNav As XPathNavigator
Dim xmlNI As XPathNodeIterator

Try
xpathDoc = DirectCast(PagesXML, XPathDocument)
xmlNav = xpathDoc.CreateNavigator()
xmlNI = xmlNav.Select("/list_pages/page")
While (xmlNI.MoveNext())
System.Console.WriteLine(xmlNI.Current.Name + " : " + xmlNI.Current.Value)
End While
Catch ex As XPathException
System.Console.WriteLine("XMLException: " + ex.Message)
Catch ex As Exception
System.Console.WriteLine("Exception: " + ex.Message)
End Try

 

[Kai77]

I solved by not defining PagesXML as an xmldocument, but as a string, so it can be read by the xmltextreader and assign the reader to the xpathdocument.

So now it looks like this:

Dim getSurveyPagesXML As New getSurveyXML
Dim PagesXML As String = getSurveyPagesXML.getXML(strFolder, "pages")

Dim xpathDoc As XPathDocument
Dim xmlNav As XPathNavigator
Dim xmlNI As XPathNodeIterator
Dim xmlreader As XmlTextReader = New XmlTextReader(PagesXML, XmlNodeType.Element, Nothing)

Try
xpathDoc = New XPathDocument(xmlreader, XmlSpace.Preserve)
xmlNav = xpathDoc.CreateNavigator()
xmlNI = xmlNav.Select("/list_pages/page")
While (xmlNI.MoveNext())
System.Console.WriteLine(xmlNI.Current.Name + " : " + xmlNI.Current.Value)
End While
Catch ex As XPathException
System.Console.WriteLine("XMLException: " + ex.Message)
Catch ex As Exception
System.Console.WriteLine("Exception: " + ex.Message)
End Try