c# 異步進度條組件BackgroundWorker

//控件事件調用DoWork()方法就行。
   
#region 進度條
        private BackgroundWorker worker = null;

        private void DoWork(string outfile)
        {
            //顯示進度條
            ProgressForm progressForm = new ProgressForm();
            progressForm.TopMost = true;
            progressForm.Show(this);

            //准備進度條的記數
            worker = new BackgroundWorker();
            //指定提供進度通知
            worker.WorkerReportsProgress = true;
            //提供中斷功能
            worker.WorkerSupportsCancellation = true;
            //線程的主要功能是處理事件
            //開啟線程執行工作
            worker.DoWork += new DoWorkEventHandler(worker_DoWork);
            // Specify the function to use to handle progress
            //指定使用的功能來處理進度
            worker.ProgressChanged += new ProgressChangedEventHandler(progressForm.OnProgressChanged);
            worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
            //進度條結束完成工作
            //1.工作完成
            //2.工作錯誤異常
            //3.取消工作
            worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(progressForm.OnProcessCompleted);
            worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
            //如果進度條需要參數
            //調用System.ComponentModel.BackgroundWorker.RunWorkerAsync
            //傳入你的參數至System.ComponentModel.BackgroundWorker.DoWork 
            //提取參數
            //System.ComponentModel.DoWorkEventArgs.Argument 

            worker.RunWorkerAsync(outfile);
        }

        //單線程執行工作
        private void worker_DoWork(object sender, DoWorkEventArgs e)
        {
            try
            {
                worker_Doing((BackgroundWorker)sender, e);
            }
            catch (Exception ex)
            {
                //此處為異常處理，不能放到worker_Doing內部
                e.Result = ex;
            }
        }

        //進行工作
        private void worker_Doing(BackgroundWorker worker, DoWorkEventArgs e)
        {
            string outfile = e.Argument as string; //傳入參數
            int count = 500;
            for (int i = 0; i < count; i++)
            {
                //檢查取消
                if (worker.CancellationPending)
                {
                    e.Cancel = true;
                    break;
                }
                else
                {
                    //此處為具體的工作代碼
                    //...

                    //進度報告
                    worker.ReportProgress((i + 1) * (100 / count), "進度信息");
                    //線程休眠
                    Thread.Sleep(500);

                }

            }

        }
        
        //進度報告
        private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            //此處可在窗口顯示進度信息
            //e.UserState as string
            //...

        }

        //工作完成狀態
        private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            string message = "";
            if (e.Error != null)
            {
                message = e.Error.Message;
                MessageBox.Show(this, message, "異常");
            }
            else if (e.Cancelled)
            {
                message = "操作被取消。";
                MessageBox.Show(this, message, "提示");
            }
            else
            {
                if (e.Result == null)
                {
                    message = "完成。";
                    MessageBox.Show(this, message, "信息");
                }
                else
                {
                    message = (e.Result as Exception).Message;
                    MessageBox.Show(this, message, "異常");
                }
            }

            //此處代碼為完成后的處理工作
            //...
        }
        #endregion