using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Windows.Forms;
namespace BackGroundWork
{
    public partial class Form1 : Form
    {
        private BackgroundWorker m_BackgroundWorker;// 申明後臺物件
        public Form1()
        {
            InitializeComponent();
            m_BackgroundWorker = new BackgroundWorker(); // 例項化後臺物件
            m_BackgroundWorker.WorkerReportsProgress = true; // 設定可以通告進度
            m_BackgroundWorker.WorkerSupportsCancellation = true; // 設定可以取消
            m_BackgroundWorker.DoWork += new DoWorkEventHandler(DoWork);//執行這個RunWorkerAsync()方法時執行
            //呼叫BackgroundWorker bw = new BackgroundWorker();bw.ReportProgress(i++);呼叫這個方法時發生
            m_BackgroundWorker.ProgressChanged += new ProgressChangedEventHandler(UpdateProgress);
            //當後臺執行完成 或被取消 或引發異常時發生
            m_BackgroundWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(CompletedWork);
            m_BackgroundWorker.RunWorkerAsync(this);
        }
        /// <summary>
        /// BackgroundWorker執行的長時間方法
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void DoWork(object sender, DoWorkEventArgs e)
        {
   //也可以直接用這個m_BackgroundWorker申明的後臺物件
            BackgroundWorker bw = sender as BackgroundWorker;
            
            int i = 0;
            while (i <= 100)
            {
//判斷應用程式是否已請求取消後臺操作
                if (bw.CancellationPending)
                {
                    e.Cancel = true;
                    break;
                }
                //注意 這裡呼叫ReportProgress(int) 方法時 會執行UpdateProgress()方法
                bw.ReportProgress(i++);
                Thread.Sleep(1000);
            }
        }
        /// <summary>
        /// 實時更新進度的方法
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void UpdateProgress(object sender, ProgressChangedEventArgs e)
        {
            int progress = e.ProgressPercentage;
            label1.Text = string.Format("{0}", progress);
        }
        /// <summary>
        /// 事件執行完成的回撥方法
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void CompletedWork(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Error != null)
            {
                MessageBox.Show("Error");//發生錯誤
            }
            else if (e.Cancelled)
            {
                MessageBox.Show("Canceled");//取消後臺
            }
            else
            {
                MessageBox.Show("Completed");//完成
            }
        }
        //請求取消後臺掛起的操作
        private void button1_Click(object sender, EventArgs e)
        {
            m_BackgroundWorker.CancelAsync();
        }
    }
}

/*BackgroundWorker傳遞引數*/
bw_DataInterface.DoWork += new DoWorkEventHandler(bw_DataInterface_DoWork);
                bw_DataInterface.RunWorkerAsync("Test parameters");
 
在DoWork Func:  DoWork(object sender, DoWorkEventArgs e)
{
   　　string tt=e.Argument.ToString();
}