程序代码：

/*

 * Created by SharpDevelop.

 * User: hellson

 * Date: 2008-10-8

 * Time: 17:00

 * 

 * To change this template use Tools | Options | Coding | Edit Standard Headers.

 */

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace draws
{
    /// <summary>
    /// Description of MainForm.
    /// </summary>
    public partial class MainForm
    {
        Form f = new Form();
        bool begin = true;
        [STAThread]
        public static void Main(string[] args)
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new MainForm());
        }
        
        public MainForm()
        {
            //
            // The InitializeComponent() call is required for Windows Forms designer support.
            //
            InitializeComponent();
            label1.Text = "等待开始被按下";
            button1.Text ="开始";
            //
            // TODO: Add constructor code after the InitializeComponent() call.
            //
        }
        
        private void Button1Click(object sender, EventArgs e)
        {
            if(begin)
                callbegin();
            else callend();
            begin = !begin;
        }
        
        void callbegin()
        {
            label1.Text = "等待<开始>被按下";
            button1.Text ="开始";
        }
        
        void callend()
        {
            label1.Text = "等待<停止>被按下";
            button1.Text ="停止";
        }
    }
}