using System;
using System.IO.Ports;	//SerialPort
using System.IO;		//Stream

namespace SampleSP
{
	class MySerialPort : SerialPort
	{
		private static Stream openedBaseStream;
		
		public MySerialPort() : base()
		{
			openedBaseStream = null;
		}
		
		public new void Open()
		{
			base.Open();
			openedBaseStream = this.BaseStream;
		}
		
		protected override void Dispose(bool disposing)
		{
			try
			{
				if (openedBaseStream != null) openedBaseStream.Close();
				openedBaseStream = null;
			}
			catch (UnauthorizedAccessException) { }
			
			base.Dispose(disposing);
		}
	}
}