Asp.net 2.0 文件下载[支持多线程, 断点续传功能](示例代码下载)

本是古典何须时尚 2021-12-17 05:34 190阅读 0赞

**(一) . 概述**

最近做了个C/S文件下载工具, 支持多任务, 多线程和断点续传功能. 其中部分代码是从网上找来的, 自己改了

许多Thread Bug, 并增加多任务, 断点续传等功能.

由于公司具有代码所有权, 不能将源代码共享. 自己对比较Asp.net感兴趣, 业余时间自己做了个简单的, 基于

Asp.net 2.0的, 目前能够执行对一个文件的下载任务, 但已经实现了多线程, 断点续传功能. 根据需要您可以增加

多任务 功能, 分享一下, 互相学习! 互相借鉴!

时间仓促, 此程序还没有做很多参数方面的优化. 可以作参考用.

**(二).运行效果**

![DownLoad.JPG][]

**(三). 代码**

1. 核心 DownLoadState.cs 文件代码

1 ///  <summary>   
  2 ///  Author: \[ ChengKing(ZhengJian) \]  
  3 ///  Blog: Http://blog.csdn.net/ChengKing  
  4 ///  注：从网上找了个优秀代码  
  5 ///  扩展如下功能:  
  6 ///  1. 解决一些线程相关的Bug;  
  7 ///  2.扩展用控制文件实现断点续传功能.  
  8 ///  </summary>   
  9 namespace  DownLoadComponent  
  10 \{  
  11  ///  <summary>   
  12  ///  多线程辅助类(Add by ChengKing)  
  13  ///  </summary>   
  14  public  class  Task  
  15  \{  
  16  string  \_FromFileName;  
  17  string  \_ToFileName;  
  18  int  \_ThreadNum;  
  19   
  20  public  Task( string  FromFileName,  string  ToFileName,  int  ThreadNum)  
  21  \{  
  22  this .\_FromFileName  =  FromFileName;  
  23  this .\_ToFileName  =  ToFileName;  
  24  this .\_ThreadNum  =  ThreadNum;  
  25  \}  
  26   
  27  public  string  FromFileName  
  28  \{  
  29  get   
  30  \{  
  31  return  \_FromFileName;  
  32  \}  
  33  set   
  34  \{  
  35  \_FromFileName  =  value;  
  36  \}  
  37  \}  
  38  public  string  ToFileName  
  39  \{  
  40  get   
  41  \{  
  42  return  \_ToFileName;  
  43  \}  
  44  set   
  45  \{  
  46  \_ToFileName  =  value;  
  47  \}  
  48  \}  
  49  public  int  ThreadNum  
  50  \{  
  51  get   
  52  \{  
  53  return  \_ThreadNum;  
  54  \}  
  55  set   
  56  \{  
  57  \_ThreadNum  =  value;  
  58  \}  
  59  \}  
  60  \}  
  61   
  62  ///  <summary>   
  63  ///  记录下载的字节位置  
  64  ///  </summary>   
  65  public  class  DownLoadState  
  66  \{  
  67  private  string  \_FileName;  
  68   
  69  private  string  \_AttachmentName;  
  70  private  int  \_Position;  
  71  private  string  \_RequestURL;  
  72  private  string  \_ResponseURL;  
  73  private  int  \_Length;  
  74   
  75  private  byte \[\] \_Data;  
  76   
  77  public  string  FileName  
  78  \{  
  79  get   
  80  \{  
  81  return  \_FileName;  
  82  \}  
  83  \}  
  84   
  85  public  int  Position  
  86  \{  
  87  get   
  88  \{  
  89  return  \_Position;  
  90  \}  
  91  \}  
  92   
  93  public  int  Length  
  94  \{  
  95  get   
  96  \{  
  97  return  \_Length;  
  98  \}  
  99  \}  
  100   
  101   
  102  public  string  AttachmentName  
  103  \{  
  104  get   
  105  \{  
  106  return  \_AttachmentName;  
  107  \}  
  108  \}  
  109   
  110  public  string  RequestURL  
  111  \{  
  112  get   
  113  \{  
  114  return  \_RequestURL;  
  115  \}  
  116  \}  
  117   
  118  public  string  ResponseURL  
  119  \{  
  120  get   
  121  \{  
  122  return  \_ResponseURL;  
  123  \}  
  124  \}  
  125   
  126   
  127  public  byte \[\] Data  
  128  \{  
  129  get   
  130  \{  
  131  return  \_Data;  
  132  \}  
  133  \}  
  134   
  135  internal  DownLoadState( string  RequestURL,  string  ResponseURL,  string  FileName,  string  AttachmentName,  int  Position,  int  Length,  byte \[\] Data)  
  136  \{  
  137  this .\_FileName  =  FileName;  
  138  this .\_RequestURL  =  RequestURL;  
  139  this .\_ResponseURL  =  ResponseURL;  
  140  this .\_AttachmentName  =  AttachmentName;  
  141  this .\_Position  =  Position;  
  142  this .\_Data  =  Data;  
  143  this .\_Length  =  Length;  
  144  \}  
  145   
  146  internal  DownLoadState( string  RequestURL,  string  ResponseURL,  string  FileName,  string  AttachmentName,  int  Position,  int  Length, ThreadCallbackHandler tch)  
  147  \{  
  148  this .\_RequestURL  =  RequestURL;  
  149  this .\_ResponseURL  =  ResponseURL;  
  150  this .\_FileName  =  FileName;  
  151  this .\_AttachmentName  =  AttachmentName;  
  152  this .\_Position  =  Position;  
  153  this .\_Length  =  Length;  
  154  this .\_ThreadCallback  =  tch;  
  155  \}  
  156   
  157  internal  DownLoadState( string  RequestURL,  string  ResponseURL,  string  FileName,  string  AttachmentName,  int  Position,  int  Length)  
  158  \{  
  159  this .\_RequestURL  =  RequestURL;  
  160  this .\_ResponseURL  =  ResponseURL;  
  161  this .\_FileName  =  FileName;  
  162  this .\_AttachmentName  =  AttachmentName;  
  163  this .\_Position  =  Position;  
  164  this .\_Length  =  Length;  
  165  \}  
  166   
  167  private  ThreadCallbackHandler \_ThreadCallback;  
  168   
  169  //  
  170  internal  void  StartDownloadFileChunk()  
  171  \{  
  172  if  ( this .\_ThreadCallback  !=  null )  
  173  \{  
  174  this .\_ThreadCallback( this .\_RequestURL,  this .\_FileName,  this .\_Position,  this .\_Length);  
  175  \}  
  176  \}  
  177   
  178  \}  
  179   
  180  // 委托代理线程的所执行的方法签名一致   
  181  public  delegate  void  ThreadCallbackHandler( string  S,  string  s,  int  I,  int  i);  
  182   
  183  // 异常处理动作   
  184  public  enum  ExceptionActions  
  185  \{  
  186  Throw,  
  187  CancelAll,  
  188  Ignore,  
  189  Retry  
  190  \}  
  191   
  192  ///  <summary>   
  193  ///  包含 Exception 事件数据的类  
  194  ///  </summary>   
  195  public  class  ExceptionEventArgs : System.EventArgs  
  196  \{  
  197  private  System.Exception \_Exception;  
  198  private  ExceptionActions \_ExceptionAction;  
  199   
  200  private  DownLoadState \_DownloadState;  
  201   
  202  public  DownLoadState DownloadState  
  203  \{  
  204  get   
  205  \{  
  206  return  \_DownloadState;  
  207  \}  
  208  \}  
  209   
  210  public  Exception Exception  
  211  \{  
  212  get   
  213  \{  
  214  return  \_Exception;  
  215  \}  
  216  \}  
  217   
  218  public  ExceptionActions ExceptionAction  
  219  \{  
  220  get   
  221  \{  
  222  return  \_ExceptionAction;  
  223  \}  
  224  set   
  225  \{  
  226  \_ExceptionAction  =  value;  
  227  \}  
  228  \}  
  229   
  230  internal  ExceptionEventArgs(System.Exception e, DownLoadState DownloadState)  
  231  \{  
  232  this .\_Exception  =  e;  
  233  this .\_DownloadState  =  DownloadState;  
  234  \}  
  235  \}  
  236   
  237  ///  <summary>   
  238  ///  包含 DownLoad 事件数据的类  
  239  ///  </summary>   
  240  public  class  DownLoadEventArgs : System.EventArgs  
  241  \{  
  242  private  DownLoadState \_DownloadState;  
  243   
  244  public  DownLoadState DownloadState  
  245  \{  
  246  get   
  247  \{  
  248  return  \_DownloadState;  
  249  \}  
  250  \}  
  251   
  252  public  DownLoadEventArgs(DownLoadState DownloadState)  
  253  \{  
  254  this .\_DownloadState  =  DownloadState;  
  255  \}  
  256   
  257  \}  
  258   
  259  ///  <summary>   
  260  ///  支持断点续传多线程下载的类  
  261  ///  </summary>   
  262  public  class  HttpWebClient  
  263  \{  
  264  private  static  object  \_SyncLockObject  =  new  object ();  
  265   
  266  public  delegate  void  DataReceiveEventHandler(HttpWebClient Sender, DownLoadEventArgs e);  
  267   
  268  public  event  DataReceiveEventHandler DataReceive;  // 接收字节数据事件   
  269   
  270  public  delegate  void  ExceptionEventHandler(HttpWebClient Sender, ExceptionEventArgs e);  
  271   
  272  public  event  ExceptionEventHandler ExceptionOccurrs;  // 发生异常事件   
  273   
  274  private  int  \_FileLength;  // 下载文件的总大小   
  275   
  276  public  static  ArrayList threads;  
  277   
  278  public  int  FileLength  
  279  \{  
  280  get   
  281  \{  
  282  return  \_FileLength;  
  283  \}  
  284  \}  
  285   
  286  ///  <summary>   
  287  ///  分块下载文件  
  288  ///  </summary>   
  289  ///  <param name="Address"> URL 地址 </param>   
  290  ///  <param name="FileName"> 保存到本地的路径文件名 </param>   
  291  ///  <param name="ChunksCount"> 块数,线程数 </param>   
  292  public  void  DownloadFile( string  Address,  string  FileName,  int  ChunksCount)  
  293  \{  
  294  int  p  =  0 ;  //  position   
  295  int  s  =  0 ;  //  chunk size   
  296  string  a  =  null ;  
  297  HttpWebRequest hwrq;  
  298  HttpWebResponse hwrp  =  null ;  
  299  try   
  300  \{  
  301   
  302  hwrq  =  (HttpWebRequest)WebRequest.Create( this .GetUri(Address));  
  303  // hwrq.Timeout = 20000000;  
  304  // if (hwrq.HaveResponse == false)  
  305  //  return;  
  306  // hwrq.ProtocolVersion =HttpVersion.Version10;  
  307  // WebProxy wp = WebProxy.GetDefaultProxy();  
  308  // hwrq.Proxy = wp;   
  309  hwrq.Method  =  " GET " ;  
  310  try   
  311  \{  
  312  hwrp  =  (HttpWebResponse)hwrq.GetResponse();  
  313  \}  
  314  catch  (Exception e)  
  315  \{  
  316  throw  new  Exception(e.Message);  
  317  \}  
  318   
  319  long  L  =  hwrp.ContentLength;  
  320   
  321  // 如果文件太小, 就不用分多线程, 用一个线程下载即可. (目前控制在800K)  
  322  // if (L < 800000)  
  323  // \{  
  324  //  ChunksCount = 1;  
  325  // \}   
  326   
  327  hwrq.Credentials  =  this .m\_credentials;  
  328   
  329  L  =  ((L  ==  \- 1 )  ||  (L  >  0x7fffffff ))  ?  (( long ) 0x7fffffff ) : L;  // Int32.MaxValue 该常数的值为 2,147,483,647; 即十六进制的 0x7FFFFFFF   
  330   
  331  int  l  =  ( int )L;  
  332   
  333  this .\_FileLength  =  l;  
  334   
  335  bool  b  =  (hwrp.Headers\[ " Accept-Ranges " \]  !=  null  &  hwrp.Headers\[ " Accept-Ranges " \]  ==  " bytes " );  
  336  a  =  hwrp.Headers\[ " Content-Disposition " \];  // attachment   
  337  if  (a  !=  null )  
  338  \{  
  339  a  =  a.Substring(a.LastIndexOf( " filename= " )  \+  9 );  
  340  \}  
  341  else   
  342  \{  
  343  a  =  FileName;  
  344  \}  
  345   
  346  int  ss  =  s;  
  347  if  (b)  
  348  \{  
  349  if  (ExistControlFile(FileName))  // 是否存在文件   
  350  \{  
  351  string \[\] strBlocks  =  this .ReadInfFromControlFile(FileName).Split( new  char \[ 2 \] \{  ' \\r ' ,  ' \\n '  \});  
  352  for  ( int  i  =  0 ; i  <  strBlocks.Length; i \++ )  
  353  \{  
  354  if  (strBlocks\[i\].Trim().Length  !=  0  &&  strBlocks\[i\].Substring(strBlocks\[i\].Length  \-  1 )  ==  " 0 " )  
  355  \{  
  356  string \[\] strRecord  =  strBlocks\[i\].Split( ' , ' );  
  357  int  p2  =  int .Parse(strRecord\[ 0 \]);  
  358  int  s2  =  int .Parse(strRecord\[ 1 \]);  
  359  DownLoadState x  =  new  DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p2, s2,  new  ThreadCallbackHandler( this .DownloadFileChunk));  
  360  Thread t  =  new  Thread( new  ThreadStart(x.StartDownloadFileChunk));  
  361  if  (threads  ==  null )  
  362  \{  
  363  threads  =  new  ArrayList();  
  364  \}  
  365  threads.Add(t);  
  366  t.Start();  
  367  \}  
  368   
  369   
  370  \}  
  371   
  372  \}  
  373  else   
  374  \{  
  375  // 建立控制文件   
  376  FileStream fs  =  File.Create( this .GetControlFileName(FileName));  
  377  fs.Close();  
  378   
  379  if  (File.Exists(FileName))  
  380  \{  
  381  FileInfo fi  =  new  FileInfo(FileName);  
  382  if  (fi.Length  ==  L)  
  383  \{  
  384  this .AddendInfToControlFile(FileName,  0 ,  0 );  
  385  this .UpdateControlFile(FileName,  0 ,  0 );  
  386  return ;  
  387  \}  
  388  \}  
  389   
  390  s  =  l  /  ChunksCount;  
  391  if  (s  <  2  \*  64  \*  1024 )  // 块大小至少为 128 K 字节   
  392  \{  
  393  s  =  2  \*  64  \*  1024 ;  
  394  \}  
  395  ss  =  s;  
  396  int  i  =  0 ;  
  397  while  (l  >=  s)  
  398  \{  
  399  l  \-=  s;  
  400  if  (l  <  s)  
  401  \{  
  402  s  \+=  l;  
  403  \}  
  404  if  (i \++  >  0 )  
  405  \{  
  406  DownLoadState x  =  new  DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s,  new  ThreadCallbackHandler( this .DownloadFileChunk));  
  407   
  408  AddendInfToControlFile(FileName, p, s);  
  409  Thread t  =  new  Thread( new  ThreadStart(x.StartDownloadFileChunk));  
  410  if  (threads  ==  null )  
  411  \{  
  412  threads  =  new  ArrayList();  
  413  \}  
  414  threads.Add(t);  
  415  t.Start();  
  416   
  417  \}  
  418  p  \+=  s;  
  419  \}  
  420  s  =  ss;  
  421   
  422  AddendInfToControlFile(FileName,  0 , s);  
  423  DownLoadState x1  =  new  DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a,  0 , s,  new  ThreadCallbackHandler( this .DownloadFileChunk));  
  424  Thread t2  =  new  Thread( new  ThreadStart(x1.StartDownloadFileChunk));  
  425  if  (threads  ==  null )  
  426  \{  
  427  threads  =  new  ArrayList();  
  428  \}  
  429  threads.Add(t2);  
  430  t2.Start();  
  431  \}  
  432  \}  
  433  // 如果服务器不支持断点续传(Accept-Range), 则使用单线程下载   
  434  else   
  435  \{  
  436  AddendInfToControlFile(FileName,  0 , l);  
  437  DownLoadState x  =  new  DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a,  0 , l,  new  ThreadCallbackHandler( this .DownloadFileChunk));  
  438  Thread t  =  new  Thread( new  ThreadStart(x.StartDownloadFileChunk));  
  439  if  (threads  ==  null )  
  440  \{  
  441  threads  =  new  ArrayList();  
  442  \}  
  443  threads.Add(t);  
  444  t.Start();  
  445  \}  
  446  \}  
  447  catch  (Exception e)  
  448  \{  
  449  // if (blnReturn == true)  
  450  // \{  
  451  //  return;  
  452  // \}   
  453   
  454  ExceptionActions ea  =  ExceptionActions.Throw;  
  455  if  (ea  ==  ExceptionActions.Throw)  
  456  \{  
  457  if  ( ! (e  is  WebException)  &&  ! (e  is  SecurityException))  
  458  \{  
  459  throw  new  WebException( " net\_webclient " , e);  
  460  \}  
  461  throw ;  
  462  \}  
  463   
  464   
  465  // if (this.ExceptionOccurrs != null)  
  466  // \{  
  467  //  DownLoadState x = new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, p, s);  
  468   
  469  //  ExceptionEventArgs eea = new ExceptionEventArgs(e, x);  
  470  //  ExceptionOccurrs(this, eea);  
  471  //  ea = eea.ExceptionAction;  
  472  // \}   
  473   
  474  \}  
  475   
  476  \}

477   
 478 \#region 操作控制文件(By King Zheng)  
 479   
 480 ///<summary>  
 481 /// 插入文件块信息到控制文件(Add by ChengKing)  
 482 ///</summary>  
 483 ///<param name="FileName"></param>  
 484 ///<param name="Position"></param>  
 485 ///<param name="Length"></param>  
 486 privatevoid AddendInfToControlFile(string FileName, int Position, int Length)  
 487  \{  
 488   
 489   
 490 try  
 491  \{  
 492 lock (\_SyncLockObject)  
 493  \{  
 494 string strControlFile = GetControlFileName(FileName);  
 495   
 496   
 497 //if (File.Exists(strControlFile) == false)  
 498 //\{  
 499 // return;  
 500 //\}  
 501   
 502 using (StreamWriter sw =new StreamWriter(strControlFile, true, Encoding.Default))  
 503  \{  
 504 //sw.NewLine = "$";  
 505  sw.WriteLine(Position.ToString() \+","\+ Length.ToString() \+","\+"0");  
 506  \}  
 507 //using (System.IO.FileStream sw = new System.IO.FileStream(strControlFile, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite))  
 508 //\{  
 509 ////sw.Position = e.DownloadState.Position;  
 510 // sw.Write(Position.ToString() + "," + Length.ToString() + "," + "0");  
 511 // sw.Close();  
 512 //\}  
 513   
 514   
 515   
 516  \}  
 517  \}  
 518 catch (Exception e)  
 519  \{  
 520 thrownew Exception("写控制文件出错!"\+ e.Message);  
 521  \}  
 522   
 523  \}  
 524   
 525 ///<summary>  
 526 /// 更新控制文件(Add by ChengKing)  
 527 ///</summary>  
 528 ///<param name="FileName"></param>  
 529 ///<param name="Position"></param>  
 530 ///<param name="Length"></param>  
 531 privatevoid UpdateControlFile(string FileName, int Position, int Length)  
 532  \{  
 533 try  
 534  \{  
 535 lock (\_SyncLockObject)  
 536  \{  
 537 string strControlFile = GetControlFileName(FileName);  
 538   
 539   
 540 //if (File.Exists(strControlFile) == false)  
 541 //\{  
 542 // return;  
 543 //\}  
 544   
 545 string s =null;  
 546 using (StreamReader sr =new System.IO.StreamReader(strControlFile))  
 547  \{  
 548  s = sr.ReadToEnd();  
 549  s = s.Replace(Position.ToString() \+","\+ Length.ToString() \+","\+"0", Position.ToString() \+","\+ Length.ToString() \+","\+"1");  
 550  \}  
 551 using (StreamWriter sw =new StreamWriter(strControlFile, false, Encoding.Default))  
 552  \{  
 553  sw.WriteLine(s);  
 554  \}  
 555  \}  
 556  \}  
 557 catch (Exception e)  
 558  \{  
 559 thrownew Exception("更新控制文件出错!"\+ e.Message);  
 560  \}  
 561   
 562  \}  
 563   
 564 ///<summary>  
 565 /// 读取所有信息从控制文件(Add by ChengKing)  
 566 ///</summary>  
 567 ///<param name="FileName"></param>  
 568 ///<returns></returns>  
 569 privatestring ReadInfFromControlFile(string FileName)  
 570  \{  
 571 try  
 572  \{  
 573 lock (\_SyncLockObject)  
 574  \{  
 575 string strControlFile = GetControlFileName(FileName);  
 576   
 577 string s =null;  
 578 using (StreamReader sr =new System.IO.StreamReader(strControlFile))  
 579  \{  
 580  s = sr.ReadToEnd();  
 581   
 582  \}  
 583 return s;  
 584  \}  
 585  \}  
 586 catch (Exception e)  
 587  \{  
 588 thrownew Exception("读控制文件出错!"\+ e.Message);  
 589  \}  
 590  \}  
 591   
 592 ///<summary>  
 593 /// 根据目标文件名得到控制文件名(Add by ChengKing)  
 594 ///</summary>  
 595 ///<param name="FileName"></param>  
 596 ///<returns></returns>  
 597 publicstring GetControlFileName(string FileName)  
 598  \{  
 599 string strPath = Path.GetDirectoryName(FileName);  
 600   
 601 //string strFileNameWithoutExtension = Path.GetFileNameWithoutExtension(FileName);  
 602 string strFileNameWithoutExtension = Path.GetFileName(FileName);  
 603 string strControlFile = Path.Combine(strPath, strFileNameWithoutExtension \+"\_Control.txt");  
 604 return strControlFile;  
 605  \}  
 606   
 607 ///<summary>  
 608 /// 判断控制文件是否存在  
 609 ///</summary>  
 610 ///<param name="FileName"></param>  
 611 ///<returns></returns>  
 612 privatebool ExistControlFile(string FileName)  
 613  \{  
 614 string strControlFile = GetControlFileName(FileName);  
 615 if (File.Exists(strControlFile))  
 616  \{  
 617 returntrue;  
 618  \}  
 619 returnfalse;  
 620  \}  
 621   
 622 ///<summary>  
 623 /// 判断控制文件是否完成  
 624 ///</summary>  
 625 ///<param name="strControlFile"></param>  
 626 ///<returns></returns>  
 627 publicbool JudgeControlFileIfFinished(string strControlFile)  
 628  \{  
 629 try  
 630  \{  
 631 string s =null;  
 632 lock (\_SyncLockObject)  
 633  \{  
 634 using (StreamReader sr =new System.IO.StreamReader(strControlFile))  
 635  \{  
 636  s = sr.ReadToEnd();  
 637  \}  
 638  \}  
 639 if (s \+ String.Empty == String.Empty)  
 640  \{  
 641 returnfalse;  
 642  \}  
 643 string\[\] strBlocks = s.Split(newchar\[2\] \{ '\\r', '\\n' \});  
 644 for (int i =0; i < strBlocks.Length; i\++)  
 645  \{  
 646 if (strBlocks\[i\].Trim().Length !=0&& strBlocks\[i\].Substring(strBlocks\[i\].Length \-1) =="0")  
 647  \{  
 648 returnfalse;  
 649  \}  
 650  \}  
 651 returntrue;  
 652   
 653  \}  
 654 catch (Exception e)  
 655  \{  
 656 thrownew Exception("判断控制文件是否完成时, 读取文件出错!"\+ e.Message);  
 657  \}  
 658  \}  
659   
 660 ///<summary>  
 661 /// 删除控制文件(Add by ChengKing)  
 662 ///</summary>  
 663 ///<param name="strControlFile"></param>  
 664 ///<returns></returns>  
 665 publicbool DeleteControlFile(string strControlFile)  
 666  \{  
 667 try  
 668  \{  
 669 lock (\_SyncLockObject)  
 670  \{  
 671 if (File.Exists(strControlFile))  
 672  \{  
 673  File.Delete(strControlFile);  
 674  \}  
 675  \}  
 676 returntrue;  
 677  \}  
 678 catch (Exception e)  
 679  \{  
 680 thrownew Exception("删除控制文件出错!"\+ e.Message);  
 681  \}  
 682  \}  
 683   
 684 \#endregion  
 685   
 686 ///<summary>  
 687 /// 下载一个文件块,利用该方法可自行实现多线程断点续传  
 688 ///</summary>  
 689 ///<param name="Address">URL 地址</param>  
 690 ///<param name="FileName">保存到本地的路径文件名</param>  
 691 ///<param name="Length">块大小</param>  
 692 publicvoid DownloadFileChunk(string Address, string FileName, int FromPosition, int Length)  
 693  \{  
 694  HttpWebResponse hwrp =null;  
 695 string a =null;  
 696 try  
 697  \{  
 698 //this.\_FileName = FileName;  
 699  HttpWebRequest hwrq = (HttpWebRequest)WebRequest.Create(this.GetUri(Address));  
 700 //hwrq.Credentials = this.m\_credentials;  
 701   
 702  hwrq.AddRange(FromPosition);  
 703   
 704  hwrp = (HttpWebResponse)hwrq.GetResponse();  
 705   
 706 //hwrp.Headers.Add("Content-Range", FromPosition.ToString()); //Test  
 707   
 708  a = hwrp.Headers\["Content-Disposition"\]; //attachment  
 709 if (a !=null)  
 710  \{  
 711  a = a.Substring(a.LastIndexOf("filename=") \+9);  
 712  \}  
 713 else  
 714  \{  
 715  a = FileName;  
 716  \}  
 717   
 718 byte\[\] buffer =this.ResponseAsBytes(Address, hwrp, Length, FileName);  
 719 // lock (\_SyncLockObject)  
 720 // \{  
 721 // this.\_Bytes += buffer.Length;  
 722 // \}  
 723  \}  
 724 catch (Exception e)  
 725  \{  
 726  ExceptionActions ea = ExceptionActions.Throw;  
 727 if (this.ExceptionOccurrs !=null)  
 728  \{  
 729  DownLoadState x =new DownLoadState(Address, hwrp.ResponseUri.AbsolutePath, FileName, a, FromPosition, Length);  
 730  ExceptionEventArgs eea =new ExceptionEventArgs(e, x);  
 731  ExceptionOccurrs(this, eea);  
 732  ea = eea.ExceptionAction;  
 733  \}  
 734   
 735 if (ea == ExceptionActions.Throw)  
 736  \{  
 737 if (!(e is WebException) &&!(e is SecurityException))  
 738  \{  
 739 thrownew WebException("net\_webclient", e);  
 740  \}  
 741 throw;  
 742  \}  
 743  \}  
 744  \}  
 745   
 746 internalbyte\[\] ResponseAsBytes(string RequestURL, WebResponse Response, long Length, string FileName)  
 747  \{  
 748 string a =null; //AttachmentName  
 749 int P =0; //整个文件的位置指针  
 750 int num2 =0;  
 751 int num3 =0;  
 752 int intFrom =0;  
 753 try  
 754  \{  
 755  a = Response.Headers\["Content-Disposition"\]; //attachment  
 756 if (a !=null)  
 757  \{  
 758  a = a.Substring(a.LastIndexOf("filename=") \+9);  
 759  \}  
 760   
 761 long num1 = Length; //Response.ContentLength;  
 762 bool flag1 =false;  
 763 if (num1 ==\-1)  
 764  \{  
 765  flag1 =true;  
 766  num1 =0x10000; //64k  
 767  \}  
 768 byte\[\] buffer1 =newbyte\[(long)num1\];  
 769   
 770   
 771 int p =0; //本块的位置指针  
 772   
 773 string s = Response.Headers\["Content-Range"\];  
 774 //string s = hwrq.Headers\["Range"\];  
 775   
 776 if (s !=null)  
 777  \{  
 778  s = s.Replace("bytes ", "");  
 779  s = s.Substring(0, s.IndexOf("\-"));  
 780  P = Convert.ToInt32(s);  
 781  intFrom = P;  
 782   
 783  \}  
 784   
 785 //int num3 = 0;  
 786   
 787  Stream S = Response.GetResponseStream();  
 788   
 789 int count =0;  
 790   
 791 int bufferSize =65535; //允许读取的最大字节  
 792   
 793 int times;  
 794 do  
 795  \{  
 796  times =0;  
 797   
 798 //num2 = S.Read(buffer1, num3, ((int)num1) - num3);  
 799   
 800 //限制最大读取字节  
 801 if (bufferSize < ((int)num1) \- num3)  
 802  \{  
 803  num2 = S.Read(buffer1, num3, bufferSize);  
 804  \}  
 805 else  
 806  \{  
 807  num2 = S.Read(buffer1, num3, ((int)num1) \- num3);  
 808  \}  
 809   
 810 //网络短时间的不稳定  
 811 if (num2 ==0)  
 812  \{  
 813  Thread.Sleep(50);  
 814  times\++;  
 815   
 816 if (times >100)  
 817  \{  
 818 thrownew Exception("网络传输层错误");  
 819  \}  
 820   
 821  \}  
 822   
 823  num3 \+= num2;  
 824 if (flag1 && (num3 == num1))  
 825  \{  
 826  num1 \+=0x10000;  
 827 byte\[\] buffer2 =newbyte\[(int)num1\];  
 828  Buffer.BlockCopy(buffer1, 0, buffer2, 0, num3);  
 829  buffer1 = buffer2;  
 830  \}  
 831   
 832 // lock (\_SyncLockObject)  
 833 // \{  
 834 // this.\_bytes += num2;  
 835 // \}  
 836 if (num2 >0)  
 837  \{  
 838 if (this.DataReceive !=null)  
 839  \{  
 840 byte\[\] buffer =newbyte\[num2\];  
 841  Buffer.BlockCopy(buffer1, p, buffer, 0, buffer.Length);  
 842  DownLoadState dls =new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2, buffer);  
 843  DownLoadEventArgs dlea =new DownLoadEventArgs(dls);  
 844   
 845 //触发事件  
 846 this.OnDataReceive(dlea);  
 847 //System.Threading.Thread.Sleep(100);   
 848   
 849  \}  
 850  p \+= num2; //本块的位置指针  
 851  P \+= num2; //整个文件的位置指针  
 852  \}  
 853 else  
 854  \{  
 855 break;  
 856  \}  
 857   
 858  \}  
 859 while (num2 !=0);  
 860   
 861  count\++;  
 862   
 863 int c = count;  
 864   
 865  S.Close();  
 866  S =null;  
 867 if (flag1)  
 868  \{  
 869 byte\[\] buffer3 =newbyte\[num3\];  
 870  Buffer.BlockCopy(buffer1, 0, buffer3, 0, num3);  
 871  buffer1 = buffer3;  
 872  \}  
 873   
 874  UpdateControlFile(FileName, intFrom, (int)Length);  
 875   
 876 return buffer1;  
 877  \}  
 878 catch (Exception e)  
 879  \{  
 880  ExceptionActions ea = ExceptionActions.Throw;  
 881 if (this.ExceptionOccurrs !=null)  
 882  \{  
 883  Thread.Sleep(100);  
 884 //DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, num2);  
 885 //DownLoadState x = new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, (int)(Length - num3));  
 886  DownLoadState x =new DownLoadState(RequestURL, Response.ResponseUri.AbsolutePath, FileName, a, P, (int)Length);  
 887   
 888  ExceptionEventArgs eea =new ExceptionEventArgs(e, x);  
 889  ExceptionOccurrs(this, eea);  
 890  ea = eea.ExceptionAction;  
 891  \}  
 892   
 893 if (ea == ExceptionActions.Throw)  
 894  \{  
 895 if (!(e is WebException) &&!(e is SecurityException))  
 896  \{  
 897 thrownew WebException("net\_webclient", e);  
 898  \}  
 899 throw;  
 900  \}  
 901 returnnull;  
 902  \}  
 903  \}

904   
 905 privatevoid OnDataReceive(DownLoadEventArgs e)  
 906  \{  
 907 //触发数据到达事件  
 908  DataReceive(this, e);  
 909  \}  
 910   
 911 publicbyte\[\] UploadFile(string address, string fileName)  
 912  \{  
 913 returnthis.UploadFile(address, "POST", fileName, "file");  
 914  \}  
 915   
 916 publicstring UploadFileEx(string address, string method, string fileName, string fieldName)  
 917  \{  
 918 return Encoding.ASCII.GetString(UploadFile(address, method, fileName, fieldName));  
 919  \}  
 920   
 921 publicbyte\[\] UploadFile(string address, string method, string fileName, string fieldName)  
 922  \{  
 923 byte\[\] buffer4;  
 924  FileStream stream1 =null;  
 925 try  
 926  \{  
 927  fileName = Path.GetFullPath(fileName);  
 928 string text1 ="\---------------------"\+ DateTime.Now.Ticks.ToString("x");  
 929   
 930 string text2 ="application/octet-stream";  
 931   
 932  stream1 =new FileStream(fileName, FileMode.Open, FileAccess.Read);  
 933  WebRequest request1 = WebRequest.Create(this.GetUri(address));  
 934  request1.Credentials =this.m\_credentials;  
 935  request1.ContentType ="multipart/form-data; boundary="\+ text1;  
 936   
 937  request1.Method = method;  
 938 string\[\] textArray1 =newstring\[7\] \{ "\--", text1, "\\r\\nContent-Disposition: form-data; name=\\"" \+ fieldName + "\\"; filename=\\"", Path.GetFileName(fileName), "\\"\\r\\nContent-Type: ", text2, "\\r\\n\\r\\n" \};  
 939 string text3 =string.Concat(textArray1);  
 940 byte\[\] buffer1 = Encoding.UTF8.GetBytes(text3);  
 941 byte\[\] buffer2 = Encoding.ASCII.GetBytes("\\r\\n--"\+ text1 \+"\\r\\n");  
 942 long num1 =0x7fffffffffffffff;  
 943 try  
 944  \{  
 945  num1 = stream1.Length;  
 946  request1.ContentLength = (num1 \+ buffer1.Length) \+ buffer2.Length;  
 947  \}  
 948 catch  
 949  \{  
 950  \}  
 951 byte\[\] buffer3 =newbyte\[Math.Min(0x2000, (int)num1)\];  
 952 using (Stream stream2 = request1.GetRequestStream())  
 953  \{  
 954 int num2;  
 955  stream2.Write(buffer1, 0, buffer1.Length);  
 956 do  
 957  \{  
 958  num2 = stream1.Read(buffer3, 0, buffer3.Length);  
 959 if (num2 !=0)  
 960  \{  
 961  stream2.Write(buffer3, 0, num2);  
 962  \}  
 963  \}  
 964 while (num2 !=0);  
 965  stream2.Write(buffer2, 0, buffer2.Length);  
 966  \}  
 967  stream1.Close();  
 968  stream1 =null;  
 969  WebResponse response1 = request1.GetResponse();  
 970   
 971  buffer4 =this.ResponseAsBytes(response1);  
 972  \}  
 973 catch (Exception exception1)  
 974  \{  
 975 if (stream1 !=null)  
 976  \{  
 977  stream1.Close();  
 978  stream1 =null;  
 979  \}  
 980 if (!(exception1 is WebException) &&!(exception1 is SecurityException))  
 981  \{  
 982 //throw new WebException(SR.GetString("net\_webclient"), exception1);  
 983 thrownew WebException("net\_webclient", exception1);  
 984  \}  
 985 throw;  
 986  \}  
 987 return buffer4;  
 988  \}  
 989

990  private  byte \[\] ResponseAsBytes(WebResponse response)  
  991  \{  
  992  int  num2;  
  993  long  num1  =  response.ContentLength;  
  994  bool  flag1  =  false ;  
  995  if  (num1  ==  \- 1 )  
  996  \{  
  997  flag1  =  true ;  
  998  num1  =  0x10000 ;  
  999  \}  
 1000  byte \[\] buffer1  =  new  byte \[( int )num1\];  
 1001  Stream stream1  =  response.GetResponseStream();  
 1002  int  num3  =  0 ;  
 1003  do   
 1004  \{  
 1005  num2  =  stream1.Read(buffer1, num3, (( int )num1)  \-  num3);  
 1006  num3  \+=  num2;  
 1007  if  (flag1  &&  (num3  ==  num1))  
 1008  \{  
 1009  num1  \+=  0x10000 ;  
 1010  byte \[\] buffer2  =  new  byte \[( int )num1\];  
 1011  Buffer.BlockCopy(buffer1,  0 , buffer2,  0 , num3);  
 1012  buffer1  =  buffer2;  
 1013  \}  
 1014  \}  
 1015  while  (num2  !=  0 );  
 1016  stream1.Close();  
 1017  if  (flag1)  
 1018  \{  
 1019  byte \[\] buffer3  =  new  byte \[num3\];  
 1020  Buffer.BlockCopy(buffer1,  0 , buffer3,  0 , num3);  
 1021  buffer1  =  buffer3;  
 1022  \}  
 1023  return  buffer1;  
 1024  \}  
 1025   
 1026  private  NameValueCollection m\_requestParameters;  
 1027  private  Uri m\_baseAddress;  
 1028  private  ICredentials m\_credentials  =  CredentialCache.DefaultCredentials;  
 1029   
 1030  public  ICredentials Credentials  
 1031  \{  
 1032  get   
 1033  \{  
 1034  return  this .m\_credentials;  
 1035  \}  
 1036  set   
 1037  \{  
 1038  this .m\_credentials  =  value;  
 1039  \}  
 1040  \}  
 1041   
 1042  public  NameValueCollection QueryString  
 1043  \{  
 1044  get   
 1045  \{  
 1046  if  ( this .m\_requestParameters  ==  null )  
 1047  \{  
 1048  this .m\_requestParameters  =  new  NameValueCollection();  
 1049  \}  
 1050  return  this .m\_requestParameters;  
 1051  \}  
 1052  set   
 1053  \{  
 1054  this .m\_requestParameters  =  value;  
 1055  \}  
 1056  \}  
 1057   
 1058  public  string  BaseAddress  
 1059  \{  
 1060  get   
 1061  \{  
 1062  if  ( this .m\_baseAddress  !=  null )  
 1063  \{  
 1064  return  this .m\_baseAddress.ToString();  
 1065  \}  
 1066  return  string .Empty;  
 1067  \}  
 1068  set   
 1069  \{  
 1070  if  ((value  ==  null )  ||  (value.Length  ==  0 ))  
 1071  \{  
 1072  this .m\_baseAddress  =  null ;  
 1073  \}  
 1074  else   
 1075  \{  
 1076  try   
 1077  \{  
 1078  this .m\_baseAddress  =  new  Uri(value);  
 1079  \}  
 1080  catch  (Exception exception1)  
 1081  \{  
 1082  throw  new  ArgumentException( " value " , exception1);  
 1083  \}  
 1084  \}  
 1085  \}  
 1086  \}  
 1087   
 1088  public  Uri GetUri( string  path)  
 1089  \{  
 1090  Uri uri1;  
 1091  try   
 1092  \{  
 1093  if  ( this .m\_baseAddress  !=  null )  
 1094  \{  
 1095  uri1  =  new  Uri( this .m\_baseAddress, path);  
 1096  \}  
 1097  else   
 1098  \{  
 1099  uri1  =  new  Uri(path);  
 1100  \}  
 1101  if  ( this .m\_requestParameters  ==  null )  
 1102  \{  
 1103  return  uri1;  
 1104  \}  
 1105  StringBuilder builder1  =  new  StringBuilder();  
 1106  string  text1  =  string .Empty;  
 1107  for  ( int  num1  =  0 ; num1  <  this .m\_requestParameters.Count; num1 \++ )  
 1108  \{  
 1109  builder1.Append(text1  \+  this .m\_requestParameters.AllKeys\[num1\]  \+  " = "  \+  this .m\_requestParameters\[num1\]);  
 1110  text1  =  " & " ;  
 1111  \}  
 1112  UriBuilder builder2  =  new  UriBuilder(uri1);  
 1113  builder2.Query  =  builder1.ToString();  
 1114  uri1  =  builder2.Uri;  
 1115  \}  
 1116  catch  (UriFormatException)  
 1117  \{  
 1118  uri1  =  new  Uri(Path.GetFullPath(path));  
 1119  \}  
 1120  return  uri1;  
 1121  \}  
 1122   
 1123  \}  
 1124   
 1125 \}  
 1126   
 1127

2.页面 Default.aspx 文件 代码

1 < html xmlns = " http://www.w3.org/1999/xhtml "  >   
  2 < head runat = " server " >   
  3  < script language = " javascript " >   
  4  mainLoop  =  function()  
  5  \{  
  6  var objPath  =  document.getElementById( " TextBox2 " );  
  7  var blnValue  =  \_Default.CheckControlFiles(objPath.value);  
  8  // a.value = a.value + blnValue.value;   
  9  if ( blnValue.value  ==  true )  
 10  \{  
 11  var returnvalue = setTimeout( ' mainLoop() ' ,  1000 );  
 12  \}  
 13  else   
 14  \{  
 15  var objStatus  =  document.getElementById( " Label1 " );  
 16  objStatus.innerText  =  " 状态: 下载完成! " ;  
 17   
 18  var btOK  =  document.getElementById( " btOK " );  
 19  btOK.disabled  =  "" ;  
 20   
 21  var btCancel  =  document.getElementById( " btCancel " );  
 22  btCancel.disabled  =  " disabled " ;  
 23   
 24  \}  
 25  \}  
 26   
 27   
 28  </ script >   
 29   
 30 </ head >   
 31 < body >   
 32  < form id = " frmTest "  runat = " server "  >   
 33  < table bgcolor = " \#ffcc66 " >< tr >< td style = " height: 259px " >   
 34  < br  />   
 35  < strong >< span style = " color: \#000099 " >   
 36  下载组件:  
 37  < br  />   
 38  1 . 支持多线程:  & nbsp;多个线程某时刻下载同一个文件的不同块. < br  />   
 39  2 . 断点续传:  & nbsp;如果下载了一个文件的某些块(一半), 则下次 < br  />   
 40  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp; 下载时只需下载未完成的块;  
 41  & nbsp;文件块的下载状 < br  />   
 42  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp; 态用控制文件记录.  
 43  块下载完成的先后顺序不 < br  />   
 44  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp;  & nbsp; 一定是连续的. < br  />   
 45  </ span ></ strong >   
 46  < br  />   
 47  < table style = " width: 379px " >   
 48  < tr >   
 49  < td colspan = " 1 "  style = " width: 87px " >   
 50  Source </ td >   
 51  < td colspan = " 2 "  style = " width: 326px " >   
 52  < asp:TextBox ID = " TextBox1 "  runat = " server "  Width = " 391px " > http: // www.</asp:TextBox></td>   
 53  </ tr >   
 54  < tr >   
 55  < td colspan = " 1 "  style = " width: 87px " >   
 56  Location </ td >   
 57  < td colspan = " 2 "  style = " width: 326px " >   
 58  < asp:TextBox ID = " TextBox2 "  runat = " server "  Width = " 391px " > D:\\Documents and Settings\\zhengjian\\桌面\\TestDownLoads\\ </ asp:TextBox ></ td >   
 59  </ tr >   
 60  < tr >   
 61  < td colspan = " 1 "  style = " width: 87px " >   
 62  Threads </ td >   
 63  < td colspan = " 2 "  style = " width: 326px " >   
 64  < asp:TextBox ID = " TextBox3 "  runat = " server "  Width = " 390px " > 10 </ asp:TextBox ></ td >   
 65  </ tr >   
 66  </ table >   
 67  < br  />   
 68  < asp:Button ID = " btOK "  runat = " server "  Text = " 下载 "  Height = " 42px "  Width = " 108px "  OnClick = " btOK\_Click "  />& nbsp;  
 69  & nbsp; < asp:Button ID = " btCancel "  runat = " server "  OnClick = " btCancel\_Click "  Text = " 取消/暂停 "  Height = " 42px "  Width = " 108px "  Enabled = " False "  />< br  />   
 70  < br  />   
 71  < asp:Label ID = " Label1 "  runat = " server "  Height = " 32px "  Text = " 状态: 未开始下载 "  Width = " 227px "  Font \- Bold = " True "  ForeColor = " \#8080FF " ></ asp:Label >< br  />   
 72  </ td ></ tr ></ table >   
 73  < script language = javascript >   
 74  mainLoop();  
 75  </ script >   
 76  </ form >   
 77 </ body >   
 78 </ html >

3. 页面后台文件 Default.aspx.cs代码

1 ///  <summary>   
  2 ///  Author: \[ ChengKing(ZhengJian) \]  
  3 ///  Blog: Http://blog.csdn.net/ChengKing  
  4 ///  注：从网上找了个优秀代码  
  5 ///  扩展如下功能:  
  6 ///  1. 解决一些线程相关的Bug;  
  7 ///  2.扩展用控制文件实现断点续传功能.  
  8 ///  </summary>   
  9 public  partial  class  \_Default : System.Web.UI.Page  
  10 \{  
  11  // 全局变量   
  12  private  static  object  \_SyncLockObject  =  new  object ();  
  13   
  14  protected  void  Page\_Load( object  sender, EventArgs e)  
  15  \{  
  16  Utility.RegisterTypeForAjax( typeof (\_Default));  
  17  // this.TextBox1.Text = " http://download.csdn.net/filedown/aHR0cDovL2Rvd25sb2FkMS5jc2RuLm5ldC9kb3duMy8yMDA3MDUwNy8wNzE4MDIwNzY4OC5yYXI= !177258";   
  18   
  19   
  20  this .TextBox1.Text  =  " http://files.cnblogs.com/ChengKing/智能象棋游戏(T1).rar " ;  
  21  \}  
  22  protected  void  btOK\_Click( object  sender, EventArgs e)  
  23  \{  
  24  this .Label1.Text  =  " 状态: 正在下载![dot.gif][] " ;  
  25   
  26  DownLoadComponent.HttpWebClient x  =  new  DownLoadComponent.HttpWebClient();  
  27   
  28  // 注册 DataReceive　事件   
  29  x.DataReceive  \+=  new  DownLoadComponent.HttpWebClient.DataReceiveEventHandler( this .x\_DataReceive);  
  30  // 注册 ExceptionOccurrs　事件   
  31  x.ExceptionOccurrs  \+=  new  DownLoadComponent.HttpWebClient.ExceptionEventHandler( this .x\_ExceptionOccurrs);  
  32   
  33  string  Source  =  this .TextBox1.Text.Trim();  
  34  string  FileName  =  Source.Substring(Source.LastIndexOf( " / " )  \+  1 );  
  35  string  Location =  System.IO.Path.Combine(  this .TextBox2.Text.Trim() , FileName);  
  36   
  37  // F: 源服务器文件; \_f: 保存路径; 10: 自设定一个文件有几个线程下载.   
  38  x.DownloadFile(Source,Location ,  int .Parse( this .TextBox3.Text));  
  39   
  40  // Response.Write("正在下载文件![dot.gif][]");   
  41  this .btOK.Enabled  =  false ;  
  42  this .btCancel.Enabled  =  true ;  
  43  \}  
  44   
  45  private  void  x\_DataReceive(DownLoadComponent.HttpWebClient Sender, DownLoadComponent.DownLoadEventArgs e)  
  46  \{  
  47   
  48  string  f  =  e.DownloadState.FileName;  
  49  if  (e.DownloadState.AttachmentName  !=  null )  
  50  f  =  System.IO.Path.GetDirectoryName(f)  \+  @" \\ "  \+  e.DownloadState.AttachmentName;  
  51   
  52  using  (System.IO.FileStream sw  =  new  System.IO.FileStream(f, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite, System.IO.FileShare.ReadWrite))  
  53  \{  
  54  sw.Position  =  e.DownloadState.Position;  
  55  sw.Write(e.DownloadState.Data,  0 , e.DownloadState.Data.Length);  
  56  sw.Close();  
  57  \}  
  58  \}  
  59   
  60  private  void  x\_ExceptionOccurrs(DownLoadComponent.HttpWebClient Sender, DownLoadComponent.ExceptionEventArgs e)  
  61  \{  
  62  System.Console.WriteLine(e.Exception.Message);  
  63  // 发生异常重新下载相当于断点续传,你可以自己自行选择处理方式或自行处理   
  64  DownLoadComponent.HttpWebClient x  =  new  DownLoadComponent.HttpWebClient();  
  65  x.DataReceive  \+=  new  DownLoadComponent.HttpWebClient.DataReceiveEventHandler( this .x\_DataReceive);  
  66  // 订阅 ExceptionOccurrs　事件  
  67  // x.ExceptionOccurrs += new DownLoadComponent.HttpWebClient.ExceptionEventHandler(this.x\_ExceptionOccurrs);   
  68   
  69  x.DownloadFileChunk(e.DownloadState.RequestURL, e.DownloadState.FileName, e.DownloadState.Position, e.DownloadState.Length);  
  70  e.ExceptionAction  =  DownLoadComponent.ExceptionActions.Ignore;  
  71  \}  
  72  protected  void  btCancel\_Click( object  sender, EventArgs e)  
  73  \{  
  74  if  (DownLoadComponent.HttpWebClient.threads  !=  null )  
  75  \{  
  76  foreach  (Thread t  in  DownLoadComponent.HttpWebClient.threads)  
  77  \{  
  78  if  (t.IsAlive)  
  79  \{  
  80  t.Abort();  
  81  \}  
  82  \}  
  83   
  84  DownLoadComponent.HttpWebClient.threads.Clear();  
  85  \}  
  86  System.Diagnostics.Process myproc  =  new  System.Diagnostics.Process();  
  87  Process\[\] procs  =  (Process\[\])Process.GetProcessesByName( " DW20.exe " );  // 得到所有打开的进程   
  88  try   
  89  \{  
  90  foreach  (Process proc  in  procs)  
  91  \{  
  92  if  (proc.CloseMainWindow()  ==  false )  
  93  \{  
  94  proc.Kill();  
  95  \}  
  96  \}  
  97  \}  
  98  catch   
  99  \{ \}  
 100  KillAllThreads();  
 101  this .btOK.Enabled  =  true ;  
 102  this .btCancel.Enabled  =  false ;  
 103  GC.Collect();  
 104   
 105  \}  
 106   
 107  ///  <summary>   
 108  ///  定期检查控制文件  
 109  ///  </summary>   
 110  ///  <param name="str"></param>   
 111  ///  <returns> 是否还继续监视(1: 正在下载中，继续监视; 0: 表示已经下载完毕,不用再检视) </returns>   
 112  \[AjaxMethod()\] //  or \[AjaxPro.AjaxMethod\]    
 113  public  bool  CheckControlFiles( string  strObjPath)  
 114  \{  
 115  if  ( ! WhetherDownloadFinished(strObjPath))  
 116  \{  
 117  return  true ;  
 118  \}  
 119  return  false ;  
 120  \}  
 121   
 122  private  bool  WhetherDownloadFinished( string  strObjPath)  
 123  \{  
 124  DirectoryInfo df  =  new  DirectoryInfo(strObjPath);  
 125  FileInfo\[\] fi  =  (FileInfo\[\])df.GetFiles( " \*.txt " , SearchOption.TopDirectoryOnly);  
 126  HttpWebClient hwc  =  new  HttpWebClient();  
 127  for  ( int  i  =  0 ; i  <  fi.Length; i \++ )  
 128  \{  
 129  if  (fi\[i\].FullName.Length  >  12  &&  fi\[i\].FullName.Substring(fi\[i\].FullName.Length  \-  12 )  ==  " \_Control.txt " )  
 130  \{  
 131  if  (hwc.JudgeControlFileIfFinished(fi\[i\].FullName)  ==  true )  
 132  \{  
 133  hwc.DeleteControlFile(fi\[i\].FullName);  
 134  KillAllThreads();  
 135  return  true ;  
 136  \}  
 137  \}  
 138  \}  
 139  return  false ;  
 140  \}  
 141   
 142  private  void  KillAllThreads()  
 143  \{  
 144  foreach  (Thread t  in  HttpWebClient.threads)  
 145  \{  
 146  if  (t.IsAlive)  
 147  \{  
 148  t.Abort();  
 149  \}  
 150  \}  
 151  HttpWebClient.threads.Clear();  
 152  \}  
 153   
 154 \}  
 155

**(四).示例代码下载**

**[http://files.cnblogs.com/MVP33650/MultiThreadDownLoadFile.rar][http_files.cnblogs.com_MVP33650_MultiThreadDownLoadFile.rar]**

**(五).Asp.net 2.0其它相关文章:**

[**http://blog.csdn.net/ChengKing/category/288694.aspx**][http_blog.csdn.net_ChengKing_category_288694.aspx]

转载于:https://www.cnblogs.com/hdjjun/archive/2008/06/17/1223891.html

[DownLoad.JPG]: /images/20211217/c08f9d83e20449cda198f1ad8374153c.png
[dot.gif]: /images/20211217/7000fd54379d4baca954d7ce687bc833.png
[http_files.cnblogs.com_MVP33650_MultiThreadDownLoadFile.rar]: http://files.cnblogs.com/MVP33650/MultiThreadDownLoadFile.rar
[http_blog.csdn.net_ChengKing_category_288694.aspx]: http://blog.csdn.net/ChengKing/category/288694.aspx