C#

XmlSerializer serializer = new XmlSerializer(typeof(OrderedItem));
OrderedItem i = new OrderedItem();
i.ItemName = "Widget";
i.Description = "Regular Widget";
i.Quantity = 10;
i.UnitPrice = (decimal) 2.30;
i.Calculate();

// Create an XmlSerializerNamespaces object.
XmlSerializerNamespaces ns = 
new XmlSerializerNamespaces();
// Add two namespaces with prefixes.
ns.Add("inventory", "http://www.cpandl.com");
ns.Add("money", "http://www.cohowinery.com");
// Create an XmlTextWriter using a FileStream.
Stream fs = new FileStream(filename, FileMode.Create);
XmlWriter writer = 
new XmlTextWriter(fs, new UTF8Encoding());
// Serialize using the XmlTextWriter.
serializer.Serialize(writer, i, ns);
writer.Close();

XNamespace root = "http://website.RFGCommonSpecListingSchema";
XNamespace xs = "http://www.w3.org/2001/XMLSchema";
XNamespace b = "http://schemas.microsoft.com/BizTalk/2003";

var doc = new XDocument(
   new XDeclaration("1.0", "utf-8", null),
   new XElement(xs + "schema",
      new XAttribute("xmlns", root.NamespaceName),
      new XAttribute(XNamespace.Xmlns + "b", b.NamespaceName),
      new XAttribute(XNamespace.Xmlns + "xs", xs.NamespaceName),
      new XAttribute("targetNamespace", "http://rfg.realogy.com/Btt/Listingfeed/Import/2011/07.RFGCommonSpecListingSchema"),
      new XAttribute("elementFormDefault", "qualified"),
      new XAttribute("attributeFormDefault", "unqualified"),
      
      // TODO: Document content goes here...
   )
);