XDocument to XmlDocument conversion and vice versa

Problem

It’s a really basic issue that I’m having. To create an XML file, I use XDocument. Then I’d like to return it as an XmlDocument object. I also have an XmlDocument variable that I need to convert to XDocument so that I can attach more nodes.

So, how do you convert XML between XDocument and XmlDocument in the most effective way? (Without employing any file-based temporary storage.)

Asked by Wim ten Brink

Solution #1

The built-in xDocument can be used. To convert back and forth, use CreateReader() and an XmlNodeReader.

To make it easier to deal with, I’m putting it into an Extension method.

using System;
using System.Xml;
using System.Xml.Linq;

namespace MyTest
{
    internal class Program
    {
        private static void Main(string[] args)
        {

            var xmlDocument = new XmlDocument();
            xmlDocument.LoadXml("<Root><Child>Test</Child></Root>");

            var xDocument = xmlDocument.ToXDocument();
            var newXmlDocument = xDocument.ToXmlDocument();
            Console.ReadLine();
        }
    }

    public static class DocumentExtensions
    {
        public static XmlDocument ToXmlDocument(this XDocument xDocument)
        {
            var xmlDocument = new XmlDocument();
            using(var xmlReader = xDocument.CreateReader())
            {
                xmlDocument.Load(xmlReader);
            }
            return xmlDocument;
        }

        public static XDocument ToXDocument(this XmlDocument xmlDocument)
        {
            using (var nodeReader = new XmlNodeReader(xmlDocument))
            {
                nodeReader.MoveToContent();
                return XDocument.Load(nodeReader);
            }
        }
    }
}

Sources:

Answered by Mark Coleman

Solution #2

This single-line solution works nicely for me.

XDocument y = XDocument.Parse(pXmldoc.OuterXml); // where pXmldoc is of type XMLDocument

Answered by Abhi

Solution #3

If you need to convert a System.Xml.Linq.XDocument instance to a System.Xml.XmlDocument instance, this extension method will ensure that the XML declaration is preserved in the resulting XmlDocument instance:

using System.Xml; 
using System.Xml.Linq;

namespace www.dimaka.com
{ 
    internal static class LinqHelper 
    { 
        public static XmlDocument ToXmlDocument(this XDocument xDocument) 
        { 
            var xmlDocument = new XmlDocument(); 
            using (var reader = xDocument.CreateReader()) 
            { 
                xmlDocument.Load(reader); 
            }

            var xDeclaration = xDocument.Declaration; 
            if (xDeclaration != null) 
            { 
                var xmlDeclaration = xmlDocument.CreateXmlDeclaration( 
                    xDeclaration.Version, 
                    xDeclaration.Encoding, 
                    xDeclaration.Standalone);

                xmlDocument.InsertBefore(xmlDeclaration, xmlDocument.FirstChild); 
            }

            return xmlDocument; 
        } 
    } 
}

Hope that helps!

Answered by Dmitry Pavlov

Solution #4

For an XmlDocument, you may try writing the XDocument to an XmlWriter piped to an XmlReader.

A direct conversion is not possible if I understand the principles well (the internal structure of XDocument is different / simplified). But then again, I could be incorrect…

Answered by Daren Thomas

Solution #5

On http://blogs.msdn.com/marcelolr/archive/2009/03/13/fast-way-to-convert-xmldocument-into-xdocument.aspx, there is a discussion.

The fastest technique appears to be reading an XDocument with an XmlNodeReader. More information can be found on the blog.

Answered by paul

Post is based on https://stackoverflow.com/questions/1508572/converting-xdocument-to-xmldocument-and-vice-versa