asp.net中上传大文件

直接在asp.net中上传大文件的方法．
方法一：在web.config中添加<httpRuntime maxRequestLength="100000" executionTimeout="45"/>
方法二：修改ＩＩＳ配置文件windows->system32->inetsrv->metaBase.xml
方法三：

1．   httpHandler or HttpModule

a.在asp.net进程处理request请求之前截获request对象
b.分块读取和写入数据
c.实时跟踪上传进度更新meta信息

2．   利用隐含的HttpWorkerRequest用它的GetPreloadedEntityBody 和 ReadEntityBody方法处理文件流

上传代码

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;
   }

 

3．   自定义Multipart MIME 解析器
自动截获MIME分割符
将文件分块写如临时文件

实时更新Appliaction 状态（ReceivingData, Error, Complete）


第三个方法不是很明白，请哪为详细解说下使用过程．