C# 从服务器下载文件代码_c# 下载服务器里的文件-优快云博客

 
 
  
  一、
  
  //
  
  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/z.zip
  
  "
  
  );
        Response.TransmitFile(filename);
    }

二、
  
  //
  
  WriteFile实现下载 
  
  

  
      
  
  protected
  
   
  
  void
  
   Button2_Click(
  
  object
  
   sender, EventArgs e)
    {
        
  
  /*
  
   
        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();
    }

三、   
  
  //
  
  WriteFile分块下载 
  
  

  
      
  
  protected
  
   
  
  void
  
   Button3_Click(
  
  object
  
   sender, EventArgs e)
    {
        
  
  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();
        }
    }

四、
  
  //
  
  流方式下载 
  
  

  
      
  
  protected
  
   
  
  void
  
   Button4_Click(
  
  object
  
   sender, EventArgs e)
    {
        
  
  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();
    }


  
  //
  
  ----------------------------------------------------------
  
  

  
  

  
  public
  
   
  
  void
  
   DownloadFile( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FileBody )
{

　　WebForm.Response.ClearHeaders();
　　WebForm.Response.Clear();
　　WebForm.Response.Expires 
  
  =
  
   
  
  0
  
  ;
　　WebForm.Response.Buffer 
  
  =
  
   
  
  true
  
  ;
　　WebForm.Response.AddHeader(
  
  "
  
  Accept-Language
  
  "
  
  , 
  
  "
  
  zh-tw
  
  "
  
  );
　　
  
  //
  
  '文件名称
  
  

  
  　　WebForm.Response.AddHeader(
  
  "
  
  content-disposition
  
  "
  
  , 
  
  "
  
  attachment; filename='
  
  "
  
  +
  
  System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8)
  
  +
  
  "
  
  '
  
  "
  
  );
　　WebForm.Response.ContentType 
  
  =
  
   
  
  "
  
  Application/octet-stream
  
  "
  
  ;
　　
  
  //
  
  '文件内容
  
  

  
  　　WebForm.Response.Write(FileBody);
  
  //
  
  -----------
  
  

  
      WebForm.Response.End();
}



  
  //
  
  上面这段代码是下载一个动态产生的文本文件，若这个文件已经存在于服务器端的实体路径，则可以通过下面的函数：
  
  

  
  

  
  public
  
   
  
  void
  
   DownloadFileByFilePath( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FilePath )
{
　　WebForm.Response.ClearHeaders();
　　WebForm.Response.Clear();
　　WebForm.Response.Expires 
  
  =
  
   
  
  0
  
  ;
    WebForm.Response.Buffer 
  
  =
  
   
  
  true
  
  ;
　　WebForm.Response.AddHeader(
  
  "
  
  Accept-Language
  
  "
  
  , 
  
  "
  
  zh-tw
  
  "
  
  );
　　
  
  //
  
  文件名称
  
  

  
  　　WebForm.Response.AddHeader(
  
  "
  
  content-disposition
  
  "
  
  , 
  
  "
  
  attachment; filename='
  
  "
  
   
  
  +
  
   System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) 
  
  +
  
  "
  
  '
  
  "
  
   );
　　WebForm.Response.ContentType 
  
  =
  
   
  
  "
  
  Application/octet-stream
  
  "
  
  ;
　　
  
  //
  
  文件内容
  
  

  
  　　WebForm.Response.Write(System.IO.File.Rea}dAllBytes(FilePath));
  
  //
  
  ---------
  
  

  
  　　WebForm.Response.End();

｝