public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            backgroundWorker1.WorkerReportsProgress = true;//報告完成進度
            backgroundWorker1.WorkerSupportsCancellation = true;//允許用戶終止后臺線程
                                                                //綁定事件
            backgroundWorker1.DoWork += new DoWorkEventHandler(backgroundWorker1_DoWork);
            backgroundWorker1.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker1_ProgressChanged);
            backgroundWorker1.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker1_RunWorkerCompleted);

        }
        //開始按鈕
        private void button1_Click(object sender, EventArgs e)
        {
            if (!backgroundWorker1.IsBusy)//判斷backgroundWorker1是否正在運行異步操作
            {
                backgroundWorker1.RunWorkerAsync(1000);//開始執(zhí)行后臺異步操作，調(diào)用DoWork事件
            }
            while (backgroundWorker1.IsBusy)//等待后臺運行完畢
            {
                Application.DoEvents();
            }
            MessageBox.Show("操作完成");
        }

        //取消按鈕
        private void button2_Click(object sender, EventArgs e)
        {
            if (backgroundWorker1.WorkerSupportsCancellation == true)
            {
                backgroundWorker1.CancelAsync();//取消后臺操作
                backgroundWorker1.Dispose();//釋放資源
            }
        }

        //DoWork事件聲明要執(zhí)行的耗時操作
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker backgroundWorker = sender as BackgroundWorker;
            e.Result = ListNumber(backgroundWorker, e);//運算結(jié)果保存在e.Result中(在RunWorkerCompleted事件可能會使用到)
        }

        bool ListNumber(object sender, DoWorkEventArgs e)
        {
            int num = (int)e.Argument;//接收傳入的參數(shù),即RunWorkerAsync(object argument)傳入的值
            for (int i = 1; i <= num; i++)
            {
                if (backgroundWorker1.CancellationPending)//判斷是否請求了取消后臺操作,如果為false則退出
                {
                    e.Cancel = true;//e.Cancel 是否應該取消事件
                    return false;
                }
                Thread.Sleep(10);//執(zhí)行一個耗時操作
                backgroundWorker1.ReportProgress(i * 100 / num, i);//報告完成進度

            }
            return true;
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {

            progressBar1.Value = e.ProgressPercentage;//將完成進度數(shù)據(jù)傳給進度條
            label1.Text = e.ProgressPercentage + "%";
            //將中間計算結(jié)果在ListBox控件中顯示出來
            listBox1.Items.Add(e.UserState);//接收ReportProgress方法傳遞過來的userState
        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled == true) //e.Cancelled指示異步操作是否已被取消
            {
                MessageBox.Show("Canceled!");
            }
            else if (e.Error != null) //e.Error 指示異步操作期間發(fā)生的錯誤
            {
                MessageBox.Show("Error: " + e.Error.Message);
            }
            else
            {
                MessageBox.Show(e.Result.ToString());  //e.Result 獲取異步操作結(jié)果的值,即DoWork事件中，Result設置的值。
            }

        }
    }

Thread thread = new Thread(SetLabel);//另開一個線程上設置Label的屬性
thread.Start();
 
delegate void Action(string args);//Net3.5自帶的Action無參數(shù)無返回值
private void SetLabel()
{
    Action action = delegate (string args)
    {
        this.label1.Text = args;
    };
    if (this.InvokeRequired)//判斷當前代碼是運行于創(chuàng)建該控件的線程之上，還是運行于另一個線程之上。
        this.Invoke(action, "XXX");//注意控件的Inovoke和BeginInvoke委托的方法都執(zhí)行在UI線程上。對Control的Invoke方法可以使用一個簡單的系統(tǒng)委托MethodInvoker無參數(shù)返回Void調(diào)用。
    else
        action("XXX");
}