The matching prefix. Or null if no matching namespace URI is found in the current scope.
Type Reason ArgumentException ns is null or string.Empty.
In the dnprdnext release, the recommended practice is to create System.Xml.XmlWriter instances using the erload:System.Xml.XmlWriter.Create method and the System.Xml.XmlWriterSettings class. This allows you to take full advantage of all the new features introduced in this release. For more information, see Creating XML Writers.