- -为了做补丁服务器就差这个下载,所以就做了这个- -测试用

https://files.cnblogs.com/ajaxren/DowonFile2008_07_27.rar  原代码用2008写的

界面,同时下栽两个(我的图画的好差啊)

newDownFile--下载类

newDownFile.ExecDown(ABDownFileChange inputDownFileChange)开始下载

 /// <summary>
 /// 更改通知进度条
/// </summary>
public class DownFileChangeProgressBar: ABDownFileChange
 

/// <summary>
    /// 不需要更改通知
    /// </summary>
  public  class DownFileNoChange: ABDownFileChange

--------------------下面的代码注意看注释啊

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.IO;
using System.Threading;

namespace DowonFile
{
    /// <summary>
    /// 新的下载类
    /// </summary>
    public class newDownFile
    {

        /// <summary>
        /// 下载文件的信息
        /// </summary>
        WebClient DownWebClientCurrent = new WebClient();


      

        /// <summary>
        ///
        /// </summary>
        public newDownFile()
        {

        }

        /// <summary>
        /// 开始下载
        /// </summary>
        public void ExecDown(ABDownFileChange inputDownFileChange)
        {


            Thread th = new Thread(new ParameterizedThreadStart(DownFileManagement));
            //--设置为后台主线程
            th.IsBackground = true;
            th.Start(inputDownFileChange);

        }

        /// 下载文件的管理者
        /// </summary>
        private void DownFileManagement(object InputDownFIleInfo)
        {
            ABDownFileChange ThreadDownFIleInfo = InputDownFIleInfo as ABDownFileChange;

            string _DownUrl = ThreadDownFIleInfo.DownUrl;
            string _saveFile = ThreadDownFIleInfo.SaveFile;


            long fbytes;
            if (_saveFile != "")
            {
                //---确定文件的长度
                fbytes = this.GetDownFileCount(ThreadDownFIleInfo.DownUrl);


                //-----读取不了
                if (fbytes == -1)
                {//--当可以通知的时候
                    if (ThreadDownFIleInfo.isChange)
                        ThreadDownFIleInfo.Error("错误");
                    return;
                }

           


                //-----------------------------下载对象，--------- 下载长度
                byte[] mbyte = this.DownFile(ThreadDownFIleInfo, fbytes);
                this.SaveFile(mbyte, _saveFile);
            }


        }

        object l = new object();
        /// <summary>
        /// 开始下载
        /// </summary>
        /// <returns></returns>
        private byte[] DownFile( ABDownFileChange inputDownFileChange,long fbytes)
        {
            Stream strm = null;
            //--这里的锁是必须的否则－在多线程访问的时候会有　i/o错误
            lock(l)
            {


           strm= DownWebClientCurrent.OpenRead(inputDownFileChange.DownUrl);

            }
            StreamReader reader = new StreamReader(strm, System.Text.Encoding.GetEncoding("gb2312"));
            byte[] mbyte = new byte[fbytes];
            int allmybyte = (int)mbyte.Length;
            int startmbyte = 0;

            ////--准许通知首先设置长度
            //if (inputDownFileChange.isChange)
            //    inputDownFileChange.setCount(allmybyte, true);


            while (fbytes > 0)
            {
                int m = strm.Read(mbyte, startmbyte, allmybyte);
                if (m == 0) break;
                startmbyte += m;
                allmybyte -= m;



                //--准许通知，---开始发送更改通知
                if (inputDownFileChange.isChange)
                    inputDownFileChange.Change(m,(int)mbyte.Length);

            }
            strm.Close();





            return mbyte;
        }

        /// <summary>
        /// 得到文件的长度
        /// </summary>
        /// <returns></returns>
        public long GetDownFileCount(string _DownUrl)
        {

            WebRequest wr_request = WebRequest.Create(_DownUrl);
            WebResponse wr_response = wr_request.GetResponse();
            long fbytes = wr_response.ContentLength;
            wr_response.Close();

            return fbytes;
        }

        /// <summary>
        /// 保存文件
        /// </summary>
        public void SaveFile(byte[] mbyte, string _saveFile)
        {
            FileStream fstrm = new FileStream(_saveFile, FileMode.OpenOrCreate, FileAccess.Write);
            fstrm.Write(mbyte, 0, mbyte.Length);
            fstrm.Close();
        }


    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DowonFile
{
    /// <summary>
    /// 当发生更改的时候通知的类
    /// </summary>
   public  abstract class ABDownFileChange
    {
        public string DownUrl;// = _downUrl;
        public string SaveFile;// = _saveFile;

       /// <summary>
       /// 是否通知
       /// </summary>
        public bool isChange = false;

       /// <summary>
       /// 不通知
       /// </summary>
        public ABDownFileChange()
        { 
        
        }

       /// <summary>
       /// 自有设定true是通知
       /// </summary>
       /// <param name="inputIsChange"></param>
        public ABDownFileChange(bool inputIsChange)
        {
            isChange = inputIsChange;
        
        }


       /// <summary>
       ///设置更改
       /// </summary>
       /// <param name="number"></param>
       public abstract void Change(int number, int count);


       /// <summary>
       /// 错误通知
       /// </summary>
       /// <param name="message"></param>
       public abstract void Error(string message);

    }
}

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Net;
using System.IO;
using System.Threading;
namespace DowonFile
{
    /// <summary>
    /// 更改
    /// </summary>
   public class DownFileChangeProgressBar : ABDownFileChange
    {
       private System.Windows.Forms.ProgressBar _progressBar;

       /// <summary>
       /// 线程用到的委托
       /// </summary>
       /// <param name="value"></param>
       delegate void StringParameterDelegate(int number,int count);

       public DownFileChangeProgressBar(System.Windows.Forms.ProgressBar InputProgressBar):base(true)
       {
           this._progressBar = InputProgressBar;
       }

  
        /// <summary>
        ///设置更改
        /// </summary>
        /// <param name="number"></param>
       public override void Change(int number, int count)
       {

          

          

           //--判断是否在ui线程中工作哦　
           if (this._progressBar.InvokeRequired)
           {

               //--这里不可以用BeginInvoke，虽然 BeginInvoke速度快，但是多次调用会出现此线程坏死的错误，应该用Invoke
               // We're not in the UI thread, so we need to call BeginInvoke
               this._progressBar.Invoke(new StringParameterDelegate(this.Change), new object[] { number,count });
               return;
           }
           // Must be on the UI thread if we've got this far，如果在直接设置
           this._progressBar.Maximum = count;
           this._progressBar.Value += number;
       
       }


        /// <summary>
        /// 错误通知
        /// </summary>
        /// <param name="message"></param>
       public override void Error(string message)
       {
           MessageBox.Show(message);
       }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DowonFile
{
    /// <summary>
    /// 不需要更改通知
    /// </summary>
  public  class DownFileNoChange: ABDownFileChange
    {
  

       public DownFileNoChange()
       {
      
       }

  
        /// <summary>
        ///设置更改
        /// </summary>
        /// <param name="number"></param>
       public override void Change(int number, int count)
       {
       }


        /// <summary>
        /// 错误通知
        /// </summary>
        /// <param name="message"></param>
       public override void Error(string message)
       {
          
       }

    }
}

----------------------------------调用

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace DowonFile
{
    public partial class test4 : Form
    { 
    //--新的下载类
    newDownFile n = new newDownFile();

        public test4()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
           //--这个乡当与下载参数
            DownFileChangeProgressBar dfcpb = new DownFileChangeProgressBar(this.progressBar1);

         


           

            saveFileDialog.ShowDialog();
            dfcpb.DownUrl = this.textBox1.Text;
            dfcpb.SaveFile=this.saveFileDialog.FileName;
              n.ExecDown(dfcpb);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //newDownFile n = new newDownFile();
            DownFileChangeProgressBar dfcpb = new DownFileChangeProgressBar(this.progressBar2);






            saveFileDialog.ShowDialog();
            dfcpb.DownUrl = this.textBox2.Text;
            dfcpb.SaveFile = this.saveFileDialog.FileName;
           n.ExecDown(dfcpb);
        }
    }
}

 看到这里在说说扩展,比如断点续传,首先要记录断开的位置,其次,保存下载的数据,然后第二次下载的时候需要从段开的地方读数据,最后在合并就可以了