Enumerate over XML data in a foreach loop

using System;
using System.IO;
using System.Xml;
using System.Collections;

namespace CustomerEnumeration
{
	/// <summary>
	/// Exposes information about customers.  This class can be enumerated over in a foreach loop.
	/// </summary>
	public class Customers : IEnumerable, IDisposable
	{
		private CustomerEnumerator custEnumerator = null;

		#region IEnumerable Members

		// When the foreach loop begins, this method is invoked so that the loop gets an enumerator to query.
		public IEnumerator GetEnumerator()
		{
			if( this.custEnumerator == null )
				this.custEnumerator = new CustomerEnumerator();
			return this.custEnumerator;
		}

		#endregion IEnumerable Members

		#region IDisposable Members

		public void Dispose()
		{
			if( this.custEnumerator != null )
				this.custEnumerator.Dispose();
		}

		#endregion
	}

	/// <summary>
	/// Exposes the customer data found in Customers.xml.
	/// </summary>
	public class CustomerEnumerator : IEnumerator, IDisposable
	{
		#region Data

		private readonly string        fileName = @"..\..\Customers.xml";
		private          XmlTextReader reader;

		#endregion Data

		#region IEnumerator Members

		public void Reset()
		{
			if( this.reader != null )
				this.reader.Close();
			System.Diagnostics.Debug.Assert( File.Exists( this.fileName ), "Customer file does not exist!" );
			StreamReader stream = new StreamReader( this.fileName );
			this.reader         = new XmlTextReader( stream );
		}

		public bool MoveNext()
		{
			// Call Reset the first time MoveNext is called instead of in the constructor 
			// so that we keep the stream open only as long as needed.
			if( this.reader == null )
				this.Reset();
			if( this.FindNextTextElement() )
				return true;
			this.reader.Close();
			return false;
		}

		public object Current
		{
			get
			{
				// No need to call FindNextTextElement here because it was called for us by MoveNext().
				string firstName = this.reader.Value;

				// Set 'val' to a default value in case the element was empty.
				string val = "";
				if( this.FindNextTextElement() )
					val = this.reader.Value;

				string lastName = val;

				// Set 'val' to a default value in case the element was empty.
				val = "0";
				if( this.FindNextTextElement() )
					val = this.reader.Value;

				int     orders;
				try   { orders = Int32.Parse( val ); }
				catch {	orders = Int32.MinValue;     }

				// Set 'val' to a default value in case the element was empty.
				val = "0";
				if( this.FindNextTextElement() )
					val = this.reader.Value;

				decimal balance;
				try   { balance = Decimal.Parse( val ); }
				catch { balance = Decimal.MinValue;     }

				return new Customer( firstName, lastName, orders, balance );
			}
		}

		#endregion

		#region Private Helper

		/// <summary>
		/// Advances the XmlTextReader to the next Text element in the XML stream.
		/// Returns true if there is more data to be read from the stream, else false.
		/// </summary>
		private bool FindNextTextElement()
		{
	bool readOn = this.reader.Read();
	bool prevTagWasElement = false;
	while( readOn && this.reader.NodeType != XmlNodeType.Text )
	{
		// If the current element is empty, stop reading and return false.
		if( prevTagWasElement &&  this.reader.NodeType == XmlNodeType.EndElement )
			readOn = false;
		prevTagWasElement = this.reader.NodeType == XmlNodeType.Element;
		readOn = readOn && this.reader.Read();
	}
	return readOn;
		}

		#endregion Private Helper

		#region IDisposable Members

		public void Dispose()
		{
			if( this.reader != null )
				this.reader.Close();
		}

		#endregion

		#region Finalizer

		~CustomerEnumerator()
		{
			this.Dispose();
		}

		#endregion // Finalizer
	}
}