'xsi' is an undeclared prefix using XmlDocument

Question

I am receiving \'xsi\' is an undeclared prefix using XmlDocument.

I am trying to read a file which has the following schema:

Answer 1

Solution:

I was able to solve the problem! Here is the final code:

XmlDocument xmldoc = new XmlDocument();
XmlReaderSettings settings = new XmlReaderSettings { NameTable = new NameTable() };
XmlNamespaceManager xmlns = new XmlNamespaceManager(settings.NameTable);
xmlns.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");
XmlParserContext context = new XmlParserContext(null, xmlns, "", XmlSpace.Default);
XmlReader reader = XmlReader.Create(strXmlFile, settings, context);
xmldoc.Load(reader);

Also one more tip, when searching through the nodes, remember to set the correct namespace, for example to search for Placemark above, this would be the format:

// Setup default namespace manager for searching through nodes
XmlNamespaceManager manager = new XmlNamespaceManager(xmldoc.NameTable);
string defaultns = xmldoc.DocumentElement.GetNamespaceOfPrefix("");
manager.AddNamespace("ns", defaultns);

// get a list of all <Placemark> nodes
XmlNodeList listOfPlacemark = xmldoc.SelectNodes("//ns:Placemark", manager);

// iterate over the <Placemark> nodes
foreach (XmlNode singlePlaceMark in listOfPlacemark)

// Get the description subnode
XmlNode descriptionNode = singlePlaceMark.SelectSingleNode("ns:description", manager);

..

Answer 2

You are missing the xsinamespace declaration:

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

now your document should look something like this:

<kml xmlns="http://www.opengis.net/kml/2.2"
          xmlns:gx="http://www.google.com/kml/ext/2.2" 
          xmlns:kml="http://www.opengis.net/kml/2.2"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xmlns:atom="http://www.w3.org/2005/Atom">
.....
</kml>