通过程序来控制下载的速度

protected void Page_Load(object sender, EventArgs e)

{

}

//调用的方法

protected void DoDownLoad(long lngSpeed)

{

Page.Response.Clear();

bool success = ResponseFile(Page.Request, Page.Response, "下载时显示的名称.rar", "E:\\WWWROOT\\downloadtest\\20090805.rar", lngSpeed);

if (!success)

{

Response.Write("下载文件出错！");

}

else

{

Response.Write("下载文件成功！");

}

Page.Response.End();

}

//主方法

public static bool ResponseFile(HttpRequest _Request, HttpResponse _Response, string _fileName, string _fullPath, long _speed)

{

try

{

FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);

BinaryReader br = new BinaryReader(myFile);

try

{

_Response.AddHeader("Accept-Ranges", "bytes");

_Response.Buffer = false;

long fileLength = myFile.Length;

long startBytes = 0;

double pack = 1024;

int sleep = (int)Math.Floor(1000 * pack / _speed) + 1;

if (_Request.Headers["Range"] != null)

{

_Response.StatusCode = 206;

string[] range = _Request.Headers["Range"].Split(new char[] { '=', '-' });

startBytes = Convert.ToInt64(range[1]);

}

_Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());

_Response.AddHeader("Connection", "Keep-Alive");

_Response.ContentType = "application/octet-stream";

_Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(_fileName, System.Text.Encoding.UTF8)); br.BaseStream.Seek(startBytes, SeekOrigin.Begin);

int maxCount = (int)Math.Floor((fileLength - startBytes) / pack) + 1;

for (int i = 0; i < maxCount; i++)

{

if (_Response.IsClientConnected)

{

_Response.BinaryWrite(br.ReadBytes(int.Parse(pack.ToString())));

Thread.Sleep(sleep);

}

else

{

i = maxCount;

}

}

}

catch (Exception e4)

{

System.Web.HttpContext.Current.Response.Write(e4.Message);

return false;

}

finally

{

br.Close();

myFile.Close();

}

}

catch (Exception e3)

{

System.Web.HttpContext.Current.Response.Write(e3.Message);

return false;

}

return true;

}

protected void Button1_Click(object sender, EventArgs e)

{

DoDownLoad(5 * 1024);

}

protected void Button2_Click(object sender, EventArgs e)

{

DoDownLoad(50 * 1024);

}