BackgroundWorker 后台线程

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Drawing;

using System.Threading;

using System.Windows.Forms;

using System.Xml;





namespace UseBackgroundWorker

{

    public partial class Form1 : Form

    {

        private XmlDocument document = null;

        public Form1()

        {

            InitializeComponent();

        }



        private void dowloadButton_Click(object sender, EventArgs e)

        {

            this.backgroundWorker1.RunWorkerAsync();



            // Disable the button for the duration of the download.

            this.dowloadButton.Enabled = false;



            // Wait for the BackgroundWorker to finish the download.

            while (this.backgroundWorker1.IsBusy)

            {

                // Keep UI messages moving, so the form remains 

                // responsive during the asynchronous operation.

                Application.DoEvents();

            }



            // The download is done, so enable the button.

            this.dowloadButton.Enabled = true;



        }



        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)

        {

            document = new XmlDocument();



            // Replace this file name with a valid file name.

            document.Load(@"http://www.tailspintoys.com/sample.xml");



            // Uncomment the following line to

            // simulate a noticeable latency.

            //Thread.Sleep(5000);



        }



        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

        {

            if (e.Error == null)

            {

                MessageBox.Show(document.InnerXml, "Download Complete");

            }

            else

            {

                MessageBox.Show(

                    "Failed to download file",

                    "Download failed",

                    MessageBoxButtons.OK,

                    MessageBoxIcon.Error);

            }



        }

    }

}