SelectsingLenode Restituisce NULL - Anche con Namespace

Question

So che questa domanda è stata posta in modo simile prima, ma non riesco a far funzionare questo.

Ho qualche XML:

<?xml version="1.0" encoding="ISO-8859-1" ?> 
    <Research xmlns="http://www.rixml.org/2005/3/RIXML" xmlns:xalan="http://xml.apache.org/xalan" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" createDateTime="2011-03-29T15:41:48Z" language="eng" researchID="MusiJvs3008">
    <Product productID="MusiJvs3008">
    <StatusInfo currentStatusIndicator="Yes" statusDateTime="2011-03-29T15:41:48Z" statusType="Published" />
    <Source>
    <Organization type="SellSideFirm" primaryIndicator="Yes">
    <OrganizationID idType="Reuters">9999</OrganizationID> 

.

E sto cercando di leggere i valori usando XPath:

XPathDocument xmldoc = new XPathDocument(xmlFile); 
XPathNavigator nav = xmldoc.CreateNavigator(); 
XmlNamespaceManager nsMgr = new XmlNamespaceManager(nav.NameTable);
nsMgr.AddNamespace(string.Empty, "http://www.rixml.org/2005/3/RIXML"); 
XPathNavigator result = nav.SelectSingleNode("/Research", nsMgr); // <-- Returns null!

.

Ma anche una semplice selezione del nodo root restituisce NULL!Sono sicuro che ho qualcosa di sbagliato nel mio spazio dei nomi.Qualcuno può aiutare?

Idealmente voglio linee semplici che mi permetteranno di selezionare i valori dal file XML, I.e.

String a = xmlDoc.SelectSingleNode(@"/Research/Product/Content/Title").Value;

.

BTW, non ho alcun controllo (diretto) sul contenuto del file XML.

Answer 1

I don't believe you can use an empty namespace alias and have it used automatically by the XPath expression. As soon as you use an actual alias, it should work though. This test is fine, for example:

using System;
using System.Xml;
using System.Xml.XPath;

class Test
{
    static void Main() 
    {
        string xmlFile = "test.xml";
        XPathDocument xmldoc = new XPathDocument(xmlFile); 
        XPathNavigator nav = xmldoc.CreateNavigator(); 
        XmlNamespaceManager nsMgr = new XmlNamespaceManager(nav.NameTable);
        nsMgr.AddNamespace("x", "http://www.rixml.org/2005/3/RIXML"); 
        XPathNavigator result = nav.SelectSingleNode("/x:Research", nsMgr);
        Console.WriteLine(result);
    }
}

Do you have to use XPath and XPathDocument, by the way? I tend to find that LINQ to XML is a much more pleasant API, particularly when it comes to namespaces. If you're using .NET 3.5 and you have no particular requirement to use XPath, I'd suggest you check it out.

Answer 2

Make the following changes

nsMgr.AddNamespace("x", "http://www.rixml.org/2005/3/RIXML"); 
XPathNavigator result = nav.SelectSingleNode("/x:Research", nsMgr);

Answer 3

i could post, and answer my own question, for the native equivalent of this code. Instead i'll just add it as an answer to the end.

When using the native IXMLDOMDocument (version 6) object:

//Give the default namespace as alias of "x"
document.setProperty("SelectionNamespaces","xmlns:x='http://www.rixml.org/2005/3/RIXML'");

//Query for the nodes we want
document.selectSingleNode("/x:Research");

Bonus Question: Why, oh why, does no Xml Document object model query the default namespace when no namespace is specified... sigh