输出硬盘文件，提供下载 支持大文件、续传、速度限制、资源占用小

///<summary>
/// 输出硬盘文件，提供下载 支持大文件、续传、速度限制、资源占用小
/// </summary>
/// <param name="MyRequest">Page.Request对象</param>
/// <param name="MyResponse">Page.Response对象</param>
/// <param name="MyFileName">下载文件名</param>
/// <param name="MyFullPath">带文件名下载路径</param>
/// <param name="MySpeed">每秒允许下载的字节数</param>
/// <returns>True Or False</returns>
public bool ResponseFile(HttpRequest MyRequest, HttpResponse MyResponse, string MyFileName, string MyFullPath, long MySpeed)
{
try
{
FileStream myFile = new FileStream(MyFullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
BinaryReader br = new BinaryReader(myFile);
try
{
MyResponse.AddHeader("Accept-Ranges", "bytes");
MyResponse.Buffer = false;

long fileLength = myFile.Length;
long startBytes = 0;
int pack = 10240; //10K bytes
int sleep = (int)Math.Floor(1000.0 * pack / MySpeed) + 1;

if (MyRequest.Headers["Range"] != null)
{
MyResponse.StatusCode = 206;
string[] range = MyRequest.Headers["Range"].Split(new char[] { '=', '-' });
startBytes = Convert.ToInt64(range[1]);
}

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

if ((startBytes != 0))
{
MyResponse.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength - 1, fileLength));
}

MyResponse.AddHeader("Connection", "Keep-Alive");
MyResponse.ContentType = "application/octet-stream";
MyResponse.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(MyFileName, System.Text.Encoding.UTF8));
br.BaseStream.Seek(startBytes, SeekOrigin.Begin);

int maxCount = (int)Math.Floor(1.0*(fileLength - startBytes) / pack) + 1;

for (int i = 0; i <= maxCount; i++)
{
if ((MyResponse.IsClientConnected))
{
MyResponse.BinaryWrite(br.ReadBytes(pack));
System.Threading.Thread.Sleep(sleep);
}
else
{
i = maxCount;
}
}
}
catch
{
return false;
}
finally
{
br.Close();myFile.Close();
}
}
catch
{
return false;
}
return true;
}

直接调用就行了.如
ResponseFile(Request, Response, "MyText.txt", @"D:/testtable.txt", 200 * 1024);