这次在项目中，用到了大文件上传，要上传的文件有100多m，于是研究现在国内使用的大文件上传的
组件发现用的比较多的有两个控件AspnetUpload 2.0和Lion.Web.UpLoadModule，另外还有思归在它的博客
堂中所说的办法 http://blog.joycode.com/saucer/archive/2004/03/16/16225.aspx
   两个控件的方法是：利用隐含的HttpWorkerRequest，用它的GetPreloadedEntityBody 和 ReadEntityBody方法从IIS为ASP.NET建立的pipe里分块读取数据。Chris Hynes为我们提供了这样的一个方案(用HttpModule)，该方案除了允许你上传大文件外，还能实时显示上传进度。
    Lion.Web.UpLoadModule和AspnetUpload 两个.NET组件都是利用的这个方案。
   当上传单文件时，两个软件的方法是一样的，继承HttpModule
       HttpApplication application1 = sender as HttpApplication;
   HttpWorkerRequest request1 = (HttpWorkerRequest) ((IServiceProvider) HttpContext.Current).GetService(typeof(HttpWorkerRequest));
   try
   {
    if (application1.Context.Request.ContentType.IndexOf("multipart/form-data") <= -1)
    {
     return;
    }
    //Check The HasEntityBody
    if (!request1.HasEntityBody())
    {
     return;
    }

    int num1 = 0;
    TimeSpan span1 = DateTime.Now.Subtract(this.beginTime);

    string text1 = application1.Context.Request.ContentType.ToLower();

    byte[] buffer1 = Encoding.ASCII.GetBytes(("\r\n--" + text1.Substring(text1.IndexOf("boundary=") + 9)).ToCharArray());
    int num2 = Convert.ToInt32(request1.GetKnownRequestHeader(11));
    Progress progress1 = new Progress();

    application1.Context.Items.Add("FileList", new Hashtable());

    byte[] buffer2 = request1.GetPreloadedEntityBody();
    num1 += buffer2.Length;

    string text2 = this.AnalysePreloadedEntityBody(buffer2, "UploadGUID");
    if (text2 != string.Empty)
    {
     application1.Context.Items.Add("LionSky_UpLoadModule_UploadGUID", text2);
    }
    bool flag1 = true;
    if ((num2 > this.UpLoadFileLength()) && ((0 > span1.TotalHours) || (span1.TotalHours > 3)))
    {
     flag1 = false;
    }
    if ((0 > span1.TotalHours) || (span1.TotalHours > 3))
    {
     flag1 = false;
    }
    string text3 = this.AnalysePreloadedEntityBody(buffer2, "UploadFolder");
    ArrayList list1 = new ArrayList();
    RequestStream stream1 = new RequestStream(buffer2, buffer1, null, RequestStream.FileStatus.Close, RequestStream.ReadStatus.NoRead, text3, flag1, application1.Context, string.Empty);
    list1.AddRange(stream1.ReadBody);
    if (text2 != string.Empty)
    {
     progress1.FileLength = num2;
     progress1.ReceivedLength = num1;
     progress1.FileName = stream1.OriginalFileName;
     progress1.FileCount = ((Hashtable) application1.Context.Items["FileList"]).Count;
     application1.Application["_UploadGUID_" + text2] = progress1;
    }
    if (!request1.IsEntireEntityBodyIsPreloaded())
    {
     byte[] buffer4;
     ArrayList list2;
     int num3 = 204800;
     byte[] buffer3 = new byte[num3];
     while ((num2 - num1) >= num3)
     {
      if (!application1.Context.Response.IsClientConnected)
      {
       this.ClearApplication(application1);
      }
      num3 = request1.ReadEntityBody(buffer3, buffer3.Length);
      num1 += num3;
      list2 = stream1.ContentBody;
      if (list2.Count > 0)
      {
       buffer4 = new byte[list2.Count + buffer3.Length];
       list2.CopyTo(buffer4, 0);
       buffer3.CopyTo(buffer4, list2.Count);
       stream1 = new RequestStream(buffer4, buffer1, stream1.FileStream, stream1.FStatus, stream1.RStatus, text3, flag1, application1.Context, stream1.OriginalFileName);
      }
      else
      {
       stream1 = new RequestStream(buffer3, buffer1, stream1.FileStream, stream1.FStatus, stream1.RStatus, text3, flag1, application1.Context, stream1.OriginalFileName);
      }
      list1.AddRange(stream1.ReadBody);
      if (text2 != string.Empty)
      {
       progress1.ReceivedLength = num1;
       progress1.FileName = stream1.OriginalFileName;
       progress1.FileCount = ((Hashtable) application1.Context.Items["FileList"]).Count;
       application1.Application["_UploadGUID_" + text2] = progress1;
      }
     }
     buffer3 = new byte[num2 - num1];
     if (!application1.Context.Response.IsClientConnected && (stream1.FStatus == RequestStream.FileStatus.Open))
     {
      this.ClearApplication(application1);
     }
     num3 = request1.ReadEntityBody(buffer3, buffer3.Length);
     list2 = stream1.ContentBody;
     if (list2.Count > 0)
     {
      buffer4 = new byte[list2.Count + buffer3.Length];
      list2.CopyTo(buffer4, 0);
      buffer3.CopyTo(buffer4, list2.Count);
      stream1 = new RequestStream(buffer4, buffer1, stream1.FileStream, stream1.FStatus, stream1.RStatus, text3, flag1, application1.Context, stream1.OriginalFileName);
     }
     else
     {
      stream1 = new RequestStream(buffer3, buffer1, stream1.FileStream, stream1.FStatus, stream1.RStatus, text3, flag1, application1.Context, stream1.OriginalFileName);
     }
     list1.AddRange(stream1.ReadBody);
     if (text2 != string.Empty)
     {
      progress1.ReceivedLength = num1 + buffer3.Length;
      progress1.FileName = stream1.OriginalFileName;
      progress1.FileCount = ((Hashtable) application1.Context.Items["FileList"]).Count;
      if (flag1)
      {
       progress1.UploadStatus = Progress.UploadStatusEnum.Uploaded;
      }
      else
      {
       application1.Application.Remove("_UploadGUID_" + text2);
      }
     }
    }
    byte[] buffer5 = new byte[list1.Count];
    list1.CopyTo(buffer5);
    this.PopulateRequestData(request1, buffer5);
   }
   catch (Exception exception1)
   {
    this.ClearApplication(application1);
    throw exception1;
   }

  而思归所说的方法使用Mime也能上传大文件，在以下地址下载
  http://krystalware.com/files/slickupload.zip
  不过觉得的思归的方法容易很多

相关文章：
让asp.net默认的上传组件支持进度条反映 
http://blog.joycode.com/dotey/archive/2005/06/12/53557.aspx // 宝玉
http://blog.joycode.com/saucer/archive/2004/03/16/16225.aspx // 思归
http://www.cnblogs.com/bestcomy/archive/2004/06/09/14267.aspx // bestcomy
http://krystalware.com/wiki/default.aspx/KrystalWiki.UploadSpike1
http://www.blueidea.com/tech/program/2005/2997.asp //ftp
通过Web Services上传和下载文件
http://dotnet.aspx.cc/ShowDetail.aspx?id=6381BD5F-51F3-4339-4239-1328564A1B2A
上传组件是如何不受settimeout限制的？
http://www.ietf.org/rfc/rfc1867.txt?number=1867

下载
http://support.microsoft.com/default.aspx?scid=kb;en-us;812406&Product=aspnet