如何使用BackgroundWorker增加多个线程
已经会使用BackgroundWorker增加后台线程，但问题是只有一个线程，访问1到1000要好几秒，速度还不会很快，我想利用BackgroundWorker增加线程，1秒之内搞定，请问如下代码如何改造呢？

BackgroundWorker bw = null;



        public Form5()

        {

            InitializeComponent();



            bw = new BackgroundWorker();

            bw.WorkerSupportsCancellation = true;

            bw.DoWork += new DoWorkEventHandler(bw_DoWork);

            bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);

        }



        void bw_DoWork(object sender, DoWorkEventArgs e)

        {

            for (int i = 1; i < 1000; i++)

            {

                if (bw.CancellationPending)

                {

                    e.Cancel = true;

                    break;

                }



                this.Invoke((MethodInvoker)delegate

                {

                    this.ShowText(String.Format("第{0}步正在执行", i));

                });

            }

        }



        void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

        {

            this.ShowText("执行完毕！");

        }



        private void button1_Click(object sender, EventArgs e)

        {

            this.button1.Enabled = false;

            this.button2.Enabled = true;



            bw.RunWorkerAsync();

        }



        private void button2_Click(object sender, EventArgs e)

        {

    &nb