.NET Fiddle

CSharp · Console

/Program.cs

using System;
using System.Xml.Linq;
using System.Linq;
using System.Text;
using System.Threading;
using System.Xml.Serialization;
using System.Xml.XPath;
public class Program
{
	public static void Main()
	{
		var xmlIn = @"<Container xmlns:i='http://www.w3.org/2001/XMLSchema-instance' xmlns='DM'>
<IsConsigned>false</IsConsigned>
<LockState>Unlocked</LockState>
<SourceType i:nil='true' />
<Id>04216194-4f62-47ee-ab21-c1053d01bf1e</Id>
<Owner>IN</Owner>
<Created>2012-08-21T09:29:10.528321+02:00</Created>
</Container>";
        var xml = XDocument.Parse(xmlIn);
		XNamespace d = "DM";
		string test = xml.Root.Element(d+"Owner").Value;
		Console.WriteLine(test);
		string id = xml.Root.Element(d+"Id").Value;
    	Console.WriteLine(id);
	}
}