/// 
        /// 下载文件        /// 
        /// 
    
     文件的路径        /// 
     
      文件名(有时候文件名存在数据库中用于替换路径中的文件名)        public void FileDownLoad(string filePath, string fileName)        {            //判断文件是否存在            if (System.IO.File.Exists(filePath))            {                FileInfo file = new FileInfo(filePath);                Response.Clear();                Response.AddHeader("Content-Disposition", "attachment; filename=" + Server.UrlEncode(fileName));//解决中文文件名乱码                   Response.AddHeader("Content-Length", file.Length.ToString());                Response.ContentType = "application/octet-stream";                Response.Filter.Close();                Response.WriteFile(file.FullName);                Response.End();            }        }