会自动弹出另存为对话框，提示用户保存路径.

会自动弹出另存为对话框，提示用户保存路径.  
   
  ///   <summary>  
    ///   文件

  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();  
  }