Parsing XSD Schema with SOM

using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
using System.Xml.Schema;
using System.Collections;

namespace UnderstandingSOM
{
    class Program
    {
        static void Main(string[] args)
        {
            TraverseSOM(args[0]);
        }

        private static XmlSchema
        ReadAndCompileSchema(string fileName)
        {
            XmlTextReader tr = new XmlTextReader(fileName,
                new NameTable());

            // The Read method will throw errors encountered
            // on parsing the schema
            XmlSchema schema = XmlSchema.Read(tr,
                new ValidationEventHandler(ValidationCallbackOne));
            tr.Close();

            XmlSchemaSet xset = new XmlSchemaSet();
            xset.Add(schema);

            xset.ValidationEventHandler += new ValidationEventHandler(ValidationCallbackOne);

            // The Compile method will throw errors 
            // encountered on compiling the schema
            xset.Compile();

            return schema;
        }

        public static void ValidationCallbackOne(object sender, ValidationEventArgs args)
        {
            Console.WriteLine("Exception Severity: " + args.Severity);
            Console.WriteLine(args.Message);
        }

        private static void TraverseSOM(string xsfFilename)
        {
            XmlSchema custSchema = ReadAndCompileSchema(xsfFilename);

            foreach (XmlSchemaElement elem in
                         custSchema.Elements.Values)
            {
                ProcessElement(elem);
            }
        }

        private static void ProcessElement(XmlSchemaElement elem)
        {
            Console.WriteLine("Element: {0}", elem.Name);

            if (elem.ElementSchemaType is XmlSchemaComplexType)
            {
                XmlSchemaComplexType ct = elem.ElementSchemaType as XmlSchemaComplexType;

                foreach (DictionaryEntry obj in ct.AttributeUses)
                    Console.WriteLine("Attribute: {0}  ", (obj.Value as XmlSchemaAttribute).Name);

                ProcessSchemaObject(ct.ContentTypeParticle);
            }
        }

        private static void ProcessSequence(XmlSchemaSequence sequence)
        {
            Console.WriteLine("Sequence");
            ProcessItemCollection(sequence.Items);
        }

        private static void ProcessChoice(XmlSchemaChoice choice)
        {
            Console.WriteLine("Choice");
            ProcessItemCollection(choice.Items);
        }

        private static void ProcessItemCollection(XmlSchemaObjectCollection objs)
        {
            foreach (XmlSchemaObject obj in objs)
                ProcessSchemaObject(obj);
        }

        private static void ProcessSchemaObject(XmlSchemaObject obj)
        {
            if (obj is XmlSchemaElement)
                ProcessElement(obj as XmlSchemaElement);
            if (obj is XmlSchemaChoice)
                ProcessChoice(obj as XmlSchemaChoice);
            if (obj is XmlSchemaSequence)
                ProcessSequence(obj as XmlSchemaSequence);
        }
    }
}