using System;

using System.IO;

using System.Xml;

​

public static class Program

{

    public static void Main(string[] args)

    {        

        var settings = new XmlWriterSettings {Indent = true};

​

    using (var sw = new StringWriter())

    {

        using (var writer = XmlWriter.Create(sw, settings))

        {

            writer.WriteStartDocument();

​

            writer.WriteStartElement("doc", "Document", @"http://www.example.com/sub");

​

                writer.WriteAttributeString("xsi", "schemaLocation", "http://www.w3.org/2001/XMLSchema-instance",

                    "http://www.example.com/sub http://www.example.com/sub/files/doc20.xsd");

​

                writer.WriteStartElement("complement12", "Complement", @"http://www.example.com/complement12");                

​

                writer.WriteAttributeString("xsi", "schemaLocation", "http://www.w3.org/2001/XMLSchema-instance",

                    "http://www.example.com/complement12 http://www.example.com/sub/files/complement12.xsd");

​

                writer.WriteAttributeString("version", "1.1");

​

                writer.WriteEndElement();

​

            writer.WriteEndElement();

​

            writer.WriteEndDocument();

        }

​

        Console.WriteLine(sw);

    }

    }

}