asp.net下载文件的常用方法

 //TransmitFile实现下载

/*
微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite
下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。代码如下：
*/
string strFileName = "三部闲置设备管理系统操作手册IEMS.ppt";
Response.ContentType = "application/x-zip-compressed";
//Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
string filename = BLL.Config.PART_EM_UPLOAD_DOC + strFileName; 
//BLL.Config.PART_EM_UPLOAD_DOC 为路径   ("D:/EMUploadDoc/")
Response.AddHeader("Content-Disposition", "attachment;filename=" +Server.UrlPathEncode(strFileName));
//Server.UrlPathEncode()解决文件名的乱码问题.
Response.TransmitFile(filename);

 

 

//WriteFile实现下载

/*
using System.IO;
*/

string fileName = "asd.txt";//客户端保存的文件名
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

FileInfo fileInfo = new FileInfo(filePath);
Response.Clear();
Response.ClearContent();
Response.ClearHeaders();
Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
Response.AddHeader("Content-Length", fileInfo.Length.ToString());
Response.AddHeader("Content-Transfer-Encoding", "binary");
Response.ContentType = "application/octet-stream";
Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");
Response.WriteFile(fileInfo.FullName);
Response.Flush();
Response.End();

 

 

//WriteFile分块下载

string fileName = "aaa.txt";//客户端保存的文件名
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);

if (fileInfo.Exists == true)
{
     const long ChunkSize = 102400;//100K 每次读取文件，只读取100Ｋ，这样可以缓解服务器的压力
      byte[] buffer = new byte[ChunkSize];

     Response.Clear();
     System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);
     long dataLengthToRead = iStream.Length;//获取下载的文件总大小
      Response.ContentType = "application/octet-stream";
     Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));
     while (dataLengthToRead > 0 && Response.IsClientConnected)
     {
         int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小
          Response.OutputStream.Write(buffer, 0, lengthRead);
         Response.Flush();
         dataLengthToRead = dataLengthToRead - lengthRead;
     }
     Response.Close();
}

 

 

//流方式下载

 

string fileName = "aaa.txt";//客户端保存的文件名
string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

//以字符流的形式下载文件
FileStream fs = new FileStream(filePath, FileMode.Open);
byte[] bytes = new byte[(int)fs.Length];
fs.Read(bytes, 0, bytes.Length);
fs.Close();
Response.ContentType = "application/octet-stream";
//通知浏览器下载文件而不是打开
Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
Response.BinaryWrite(bytes);
Response.Flush();
Response.End();