Asp.net(c#)实现多线程断点续传

System.IO.StreamiStream=null;

//Buffertoread10Kbytesinchunk:
byte[]buffer=newByte[10240];

//Lengthofthefile:
intlength;

//Totalbytestoread:
longdataToRead;

//Identifythefiletodownloadincludingitspath.
stringfilepath=@"E:/software/SQLServer2000PersonalEdition.ISO";

//Identifythefilename.
stringfilename=System.IO.Path.GetFileName(filepath);

try
{
//Openthefile.
iStream=newSystem.IO.FileStream(filepath,System.IO.FileMode.Open,
System.IO.FileAccess.Read,System.IO.FileShare.Read);
Response.Clear();

//Totalbytestoread:
dataToRead=iStream.Length;

longp=0;
if(Request.Headers["Range"]!=null)
{
Response.StatusCode=206;
p=long.Parse(Request.Headers["Range"].Replace("bytes=","").Replace("-",""));
}
if(p!=0)
{
Response.AddHeader("Content-Range","bytes"+p.ToString()+"-"+((long)(dataToRead-1)).ToString()+"/"+dataToRead.ToString());
}
Response.AddHeader("Content-Length",((long)(dataToRead-p)).ToString());
Response.ContentType="application/octet-stream";
Response.AddHeader("Content-Disposition","attachment;filename="+System.Web.HttpUtility.UrlEncode(Request.ContentEncoding.GetBytes(filename)));

iStream.Position=p;
dataToRead=dataToRead-p;
//Readthebytes.
while(dataToRead>0)
{
//Verifythattheclientisconnected.
if(Response.IsClientConnected)
{
//Readthedatainbuffer.
length=iStream.Read(buffer,0,10240);

//Writethedatatothecurrentoutputstream.
Response.OutputStream.Write(buffer,0,length);

//FlushthedatatotheHTMLoutput.
Response.Flush();

buffer=newByte[10240];
dataToRead=dataToRead-length;
}
else
{
//preventinfiniteloopifuserdisconnects
dataToRead=-1;
}
}
}
catch(Exceptionex)
{
//Traptheerror,ifany.
Response.Write("Error:"+ex.Message);
}
finally
{
if(iStream!=null)
{
//Closethefile.
iStream.Close();
}
Response.End();
}