using System;
using System.IO;
using System.Xml;
using System.Xml.Serialization;

namespace ConsoleApplication1
{
  public class Program
  {
    const string Xml = @"<?xml version='1.0' encoding='utf-16'?>
<ChordType name='C Minor' priority='Important'>
  <description>C minor</description>
  <abbreviations>
    <abbr category='General'>m</abbr>
    <abbr category='Jazz'>-</abbr>
    <abbr category='Full'>min</abbr>
  </abbreviations>
  <intervals>
    <interval quality='Perfect' number='Unison' />
    <interval quality='Minor' number='Third' />
    <interval quality='Perfect' number='Fifth' />
  </intervals>
</ChordType>";

    static void Main(string[] args)
    {
      ChordType ct;
      var serializer = new XmlSerializer(typeof(ChordType));
      using (var sr = new StringReader(Xml))
        ct = (ChordType)serializer.Deserialize(sr);

    }

    public class ChordType : IXmlSerializable
    {

      public System.Xml.Schema.XmlSchema GetSchema()
      {
        return null;
      }

      public void ReadXml(XmlReader reader)
      {
        Console.WriteLine("Name: {0}", reader.GetAttribute("name"));
        Console.WriteLine("Priority: {0}", reader.GetAttribute("priority"));
        if (reader.ReadToFollowing("description"))
          Console.WriteLine("Description: {0}", reader.ReadElementContentAsString());

        if (reader.Name != "abbreviations")
          throw new InvalidOperationException("Abbreviations element missing.");
        if (!reader.ReadToDescendant("abbr"))
          throw new InvalidOperationException("At least one abbreviation element is required.");
        var i = 0;
        do
          Console.WriteLine("Abbreviation {0} - Category: {1}, Abbr: {2}", ++i, reader.GetAttribute("category"), reader.ReadElementContentAsString());
        while (reader.ReadToNextSibling("abbr"));


        if (!reader.ReadToFollowing("intervals"))
          //here's where the code fails
          throw new InvalidOperationException("Intervals element missing.");
        i = 0;
        do
          Console.WriteLine("Interval {0} - quality: {1}, abbr: {2}", ++i, reader.GetAttribute("quality"), reader.GetAttribute("number"));
        while (reader.ReadToNextSibling("interval"));
      }

      public void WriteXml(System.Xml.XmlWriter writer)
      {
        throw new NotImplementedException();
      }
    }
  }
}