using?System;
using?System.Collections.Generic;
using?System.ComponentModel;
using?System.Data;
using?System.Drawing;
using?System.Linq;
using?System.Text;
using?System.Windows.Forms;
using?System.Diagnostics;//提供一組方法和屬性，可用于準確地測量運行時間只有引用后Stopwatch類才能使用
using?System.Threading;//創建和控制線程，設置其優先級并獲取其狀態。

namespace?秒表計時器
{
????public?partial?class?Form1?:?Form
????{
????????private?BackgroundWorker?demoBGWorker?=?new?BackgroundWorker（）;

????????public?Form1（）
????????{
????????????InitializeComponent（）;


????????}

????????private?void?Form1_Load（object?sender?EventArgs?e）
????????{
????????????timer1.Enabled?=?false;
????????????timer1.Interval?=?500;
????????}

????????int?timerDrawI?=?0;
????????float?timerDrawF?=?0;
????????private?void?timer1_Tick（object?sender?EventArgs?e）
????????{
????????????timerDrawI++;
????????????timerDrawF?=?timerDrawI?/?2;
????????????textBox_ms.Text?=?Convert.ToString（timerDrawI）;
????????????textBox_sec.Text?=?Conver