using

 System;

using System.ComponentModel;

using

 System.Windows.Forms;

namespace

 WindowsApplication4

{

    /// <summary>

    /// gui 类

    /// </summary>

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)

        {

            //用子线程工作

            new System.Threading.Thread(new System.Threading.ThreadStart(StartDownload)).Start();

        }

        //开始下载

        public void StartDownload()

        {

            Downloader downloader = new Downloader();

            downloader.onDownLoadProgress += new Downloader.dDownloadProgress(downloader_onDownLoadProgress);

            downloader.Start();

        }

        //同步更新ui

        void downloader_onDownLoadProgress(long total, long current)

        {

            if (this.InvokeRequired)

            {

                this.Invoke(new Downloader.dDownloadProgress(downloader_onDownLoadProgress), new object[] { total, current });

            }

            else

            {

                this.progressBar1.Maximum = (int)total;

                this.progressBar1.Value = (int)current;

            }

        }

    }

    /// <summary>

    /// 下载类

    /// </summary>

    public class Downloader

    {

        //委托

        public delegate void dDownloadProgress(long total,long current);

        //事件

        public event dDownloadProgress onDownLoadProgress;

        //开始模拟工作

        public void Start()

        {

            for (int i = 0; i < 100; i++)

            {

                if (onDownLoadProgress != null)

                    onDownLoadProgress(100, i);

                System.Threading.Thread.Sleep(100);

            }

        }

    }