asp.net文件下载类

asp教程.net文件下载类
<%@ Page Language="VB" ContentType="text/html" ResponseEncoding="gb2312" %>
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<%
'件下载类是什么意思？
实现下载功能？
DownloadData 方法通过 address 参数指定的 URI 下载资源。此方法在下载资源时阻止。若要下载资源并在等待服务器响应的同时继续执行，请使用 DownloadDataAsync 方法之一。

如果 BaseAddress 属性不是空字符串 ("")，且 address 不包含绝对 URI，则 address 必须是相对 URI，此 URI 与 BaseAddress 组合在一起构成所请求数据的绝对 URI。如果 QueryString 属性不是空字符串，则将它追加到 address。

此方法使用 RETR 命令下载 FTP 资源。对于 HTTP 资源，使用 GET 方法。
下面的代码示例从服务器请求数据并显示所返回的数据。它假设 remoteUri 包含所请求的数据的有效 URI。

private void FileDownload(string FullFileName)

　　{

　　FileInfo DownloadFile = new FileInfo(FullFileName);

　　Response.Clear();

　　Response.ClearHeaders();

　　Response.Buffer = false;

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

　　Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(DownloadFile.FullName, System.Text.Encoding.UTF8));

　　Response.AppendHeader("Content-Length", DownloadFile.Length.ToString());

　　Response.WriteFile(DownloadFile.FullName);

　　Response.Flush();

　　Response.End();

　　}

　　调用方法

　　string path= Server.MapPath("fujian/"+文件名称);//path为服务器存放文件的路径

　　FileDownload(path);
'文件下载类方法二

public class FileHelper
    {
        ///

        /// 利用Base64码对文件名进行加密处理。
        ///

        /// 文件名
        ///
        public static string Encrypt(string filename)
        {
            byte[] buffer = HttpContext.Current.Request.ContentEncoding.GetBytes(filename);
            return HttpUtility.UrlEncode(Convert.ToBase64String(buffer));
        }

        ///

        /// 利用Base64码对文件名进行解密处理。
        ///

        /// 文件名
        ///
        public static string Decrypt(string encryptfilename)
        {
            byte[] buffer = Convert.FromBase64String(encryptfilename);
            return HttpContext.Current.Request.ContentEncoding.GetString(buffer);
        }
    }

'方法三

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;
                    }
                }
            }
            catch
            {
             return false;
            }
            finally
            {
                br.Close();

                myFile.Close();
            }
        }
        catch
        {
            return false;
        }
        return true;
    }
 '调用 方法在Page_Load加入
 Page.Response.Clear();
  bool success = ResponseFile(Page.Request, Page.Response, "目的文件名称", @"源文件路径", 1024000);
  if (!success)
   Response.Write("下载文件出错！");
 Page.Response.End();

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