using System;

using System.Xml.Serialization;

using System.IO;

using System.Xml.Linq;

using System.Linq;

​

​

public static class Extensions {

public static XElement StripNs(this XElement rootElement)

        {

            foreach (var element in rootElement.DescendantsAndSelf())

            {

                // update element name if a namespace is available

                if (element.Name.Namespace != XNamespace.None)

                {

                    element.Name = XNamespace.None.GetName(element.Name.LocalName);

                }

​

                // check if the element contains attributes with defined namespaces (ignore xml and empty namespaces)

                bool hasDefinedNamespaces = element.Attributes().Any(attribute => attribute.IsNamespaceDeclaration ||

                        (attribute.Name.Namespace != XNamespace.None && attribute.Name.Namespace != XNamespace.Xml));

​

                if (hasDefinedNamespaces)

                {

                    // ignore attributes with a namespace declaration

                    // strip namespace from attributes with defined namespaces, ignore xml / empty namespaces

                    // xml namespace is ignored to retain the space preserve attribute

                    var attributes = element.Attributes()

                                            .Where(attribute => !attribute.IsNamespaceDeclaration)

                                            .Select(attribute =>

                                                (attribute.Name.Namespace != XNamespace.None && attribute.Name.Namespace != XNamespace.Xml) ?

                                                    new XAttribute(XNamespace.None.GetName(attribute.Name.LocalName), attribute.Value) :

                                                    attribute

                                            );

​

                    // replace with attributes result

                    element.ReplaceAttributes(attributes);

                }

            }

            return rootElement;

        }

}

​

public class Program

{

​

    public static void Main()

    {

        string xml = @"<?xml version=""1.0"" encoding=""UTF-8""?>

        <FluxPivotAVE xmlns=""http://transactions.grtgaz.com/pub/avisequilibrage"">

            <Header xmlns=""http://transactions.grtgaz.com/pub/avisequilibragecookie"">

                <Version>5</Version>

                <Type>AVE</Type>        

            </Header>

        </FluxPivotAVE>";

        var rootElement = XElement.Parse(xml).StripNs();

        Console.WriteLine("Root Default namespace: {0}",rootElement.GetDefaultNamespace());  

        XElement header = rootElement.Element("Header");

        Console.WriteLine(header != null ? "Ok" : "Ko");

        Console.WriteLine("Header Default namespace: {0}",header.GetDefaultNamespace());  

    }

}