public partial class Form1 : Form
    {
 
        public Form1()
        {
            InitializeComponent();
        }
 
        private void btnStart_Click(object sender, EventArgs e)
        {
            if (bgWorker.IsBusy)              //判斷是否正在運行異步操作
                return;
            this.progressBar1.Maximum = 100;  //設置進度條最大值
            this.btnStart.Enabled = false;
            this.btnStop.Enabled = true;
            bgWorker.RunWorkerAsync("11111");   //給業務傳遞參數，就是把前臺的要處理的參數傳遞進去
        }
 
        public void bgWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            //業務處理
            object s = e.Argument;   //這的e.Argument就是上面傳遞的參數 11111
            for (int i = 0; i <= this.progressBar1.Maximum; i++)
            {
                if (bgWorker.CancellationPending)     //此處關聯的是btnStop_Click事件中的這個bgWorker.CancelAsync();如果這個觸發了，那么就會停止。
                {
                    e.Cancel = true;
                    return;
                }
                else
                {
                    bgWorker.ReportProgress(i, "222222"); //向bgWorker_ProgessChanged事件傳遞參數，第一個是進度的參數，第二個是你要處理業務的參數
                    System.Threading.Thread.Sleep(1);
                }
            }
        }
 
        public void bgWorker_ProgessChanged(object sender, ProgressChangedEventArgs e)
        {
            //頁面處理
            string state = (string)e.UserState;//接收上bgWorker.ReportProgress方法傳遞過來的參數userState
            this.progressBar1.Value = e.ProgressPercentage;
            this.label1.Text = "處理進度:" + Convert.ToString(e.ProgressPercentage) + "%";
            //label2.Text = e.ProgressPercentage.ToString();
        }
 
        public void bgWorker_WorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Error != null)
            {
                MessageBox.Show(e.Error.ToString());
                return;
            }
            if (!e.Cancelled)
                this.label1.Text = "處理完畢!";
            else
                this.label1.Text = "處理終止!";
 
        }
 
        private void btnStop_Click(object sender, EventArgs e)
        {
            this.btnStart.Enabled = true;
            this.btnStop.Enabled = false;
            bgWorker.CancelAsync();
        }
 
    }