private void btnGo_Click(object sender, EventArgs e)
        {
            if (btnGo.Text=="执行")
            {
                this.Text = "执行中";
                btnGo.Text = "停止";
                System.Threading.Thread t = new System.Threading.Thread(new System.Threading.ThreadStart(EmulateLongProcess));
                t.Start();
            }
            else
            {
                isCanceled = true;
                this.Text = "已经停止";
                btnGo.Text = "执行";
            }
        }
        private void EmulateLongProcess()
        {
            isCanceled = false;
            for (int i = 1; i <= 500000;i++ )
            {
                if (isCanceled==true)
                {
                    break;
                }
                //System.Threading.Thread.Sleep(10);
                int j = System.Threading.Thread.CurrentThread.ManagedThreadId;
                double precentDone = (Convert.ToDouble(i) / 500000) * 100;
                UpdateProgress(precentDone);
            }
        }
        private delegate void UpdateProgressDelegate(double precentDone);
        private void UpdateProgress(double precentDone)
        {
            if (InvokeRequired==true)
            {
                BeginInvoke(new UpdateProgressDelegate(UpdateProgress), new object[] { precentDone });
                return;
            }
            if (precentDone==0)
            {
                isCanceled = true;
            }
            if (isCanceled)
            {
                progressBar.Value = 0;
            }
            else
            {
                progressBar.Value = Convert.ToInt16(precentDone);
            }
            statuslable.Text = progressBar.Value.ToString() + "%完成";
            if (precentDone==0)
            {
                statuslable.Text = string.Empty;
            }
        }