C#结合串口通信类实现串口通信源代码

mycom是串口通信类，在本blog前一篇中有完整代码。
下面是串口通讯测试程序的源代码，将mycom类放在此项目中
可以实现简单的串口通信，希望读者能通过这个程序对串口通信过程有一个初步的了解：

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Threading;
namespace BusApp
{
/// <summary>
/// Form1 的摘要说明。
/// </summary>
public class Form1 : System.Windows.Forms.Form
{
  private System.Windows.Forms.Label label1;
  private System.Windows.Forms.Label label2;
  private System.Windows.Forms.Button button1;
  private System.Windows.Forms.GroupBox groupBox1;
  private System.Windows.Forms.Label label3;
  private System.Windows.Forms.Label label4;
  private System.Windows.Forms.Label label5;
  private System.Windows.Forms.Label label6;
  private System.Windows.Forms.Button button2;
  private System.Windows.Forms.Button button3;
  private System.Windows.Forms.Button button4;
  private System.Windows.Forms.TextBox textBox8;
  private System.Windows.Forms.Label label7;

  public int iPort=1; //1,2,3,4
  public int iRate=9600; //1200,2400,4800,9600
  public byte bSize=8; //8 bits
  public byte bParity=0; // 0-4=no,odd,even,mark,space
  public byte bStopBits=1; // 0,1,2 = 1, 1.5, 2
  public int iTimeout=1000;
  public mycom mycom1=new mycom();
  public byte[] recb;

  private System.Windows.Forms.TextBox msg;
  private System.Windows.Forms.TextBox t_port;
  private System.Windows.Forms.TextBox t_rate;
  private System.Windows.Forms.TextBox t_bytesize;
  private System.Windows.Forms.TextBox t_stopbyte;
  private System.Windows.Forms.TextBox t_parity;
  private System.Windows.Forms.TextBox t_send;
  private System.Windows.Forms.Button button5; //readTimeOut
  /// <summary>
  /// 必需的设计器变量。
  /// </summary>
  private System.ComponentModel.Container components = null;

  public Form1()
  {
   InitializeComponent();
  }

  /// <summary>
  /// 清理所有正在使用的资源。
  /// </summary>
  protected override void Dispose( bool disposing )
  {
   if( disposing )
   {
    if (components != null)
    {
     components.Dispose();
    }
   }
   base.Dispose( disposing );
  }

  #region Windows 窗体设计器生成的代码
  /// <summary>
  /// 设计器支持所需的方法 - 不要使用代码编辑器修改
  /// 此方法的内容。
  /// </summary>
  private void InitializeComponent()
  {
   this.msg = new System.Windows.Forms.TextBox();
   this.label1 = new System.Windows.Forms.Label();
   this.label2 = new System.Windows.Forms.Label();
   this.t_send = new System.Windows.Forms.TextBox();
   this.button1 = new System.Windows.Forms.Button();
   this.groupBox1 = new System.Windows.Forms.GroupBox();
   this.button2 = new System.Windows.Forms.Button();
   this.t_po