asp.net实现下载

 

// TransmitFile实现下载
     protected   void  Button1_Click( object  sender, EventArgs e)
    {
         /*
         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：
          */

        Response.ContentType  =   " application/x-zip-compressed " ;
        Response.AddHeader( " Content-Disposition " ,  " attachment;filename=z.zip " );
         string  filename  =  Server.MapPath( " DownLoad/aaa.zip " );
        Response.TransmitFile(filename);
    }

     // WriteFile实现下载
     protected   void  Button2_Click( object  sender, EventArgs e)
    {
         /*
         using System.IO;
         
          */

         string  fileName  = " aaa.zip " ; // 客户端保存的文件名
         string  filePath = Server.MapPath( " DownLoad/aaa.zip " ); // 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
     protected   void  Button3_Click( object  sender, EventArgs e)
    {

         string  fileName  =   " aaa.zip " ; // 客户端保存的文件名
         string  filePath  =  Server.MapPath( " DownLoad/aaa.zip " ); // 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
     protected   void  Button4_Click( object  sender, EventArgs e)
    {
         string  fileName  =   " aaa.zip " ; // 客户端保存的文件名
         string  filePath  =  Server.MapPath( " DownLoad/aaa.zip " ); // 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();

    }

 源码下载： http://download1.csdn.net/down3/20070512/12000756854.rar