C#中使用HttpDownLoadHelper下载文件实例

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;
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
                        {
                            i = maxcount;
                        }
                    }
                    return true;
                }
                catch
                {
                    return false;
                }
                finally
                {
                    br.close();

                    myfile.close();
                }
            }
            catch
            {
                return false;
            }
        }
    }
}

httpdownloadhelper

在webfrom中:

string filepath=path.combine(httpruntime.appdomainapppath,"files","项目管理工具.msi");
httpdownloadhelper.responsefile(request, response, "下载显示的名称", filepath, 102400);

在mvc中:

string filepath=path.combine(httpruntime.appdomainapppath,"files","项目管理工具.msi");
httpdownloadhelper.responsefile(httpcontext.applicationinstance.context.request, httpcontext.applicationinstance.context.response, "下载显示的名称", filepath, 102400);

希望本文所述对大家的c#程序设计有所帮助。