本文实例讲述了C#使用HttpDownLoadHelper下载文件的方法。分享给大家供大家参考。具体实现方法如下：
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Threading;
namespace ProjectWenDangManage.Framework
{
/// <summary>
/// HTTP文件下载辅助类
/// </summary>
public class HttpDownLoadHelper
{
/// <summary>
/// 文件下载
/// </summary>
/// <param name="_Request"></param>
/// <param name="_Response"></param>
/// <param name="_fileName">下载文件时的短文件名称</param>
/// <param name="_fullPath">待下载文件的绝对路径</param>
/// <param name="_speed">下载速度</param>
/// <returns></returns>
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 = 10240; //10K bytes
//int sleep = 200; //每秒5次 即5*10K bytes每秒
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());
if (startBytes != 0)
{
//Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength-1, fileLength));
}
_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
{
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