asp.net-log-write

 string logFile = "log-" + DateTime.Now.ToString("yyyyMMdd") + ".txt";
            string filePath = WebConfigurationManager.AppSettings["LogPath"].ToString();
            //example   --- c:/website/Logs/
            if (!string.IsNullOrEmpty(filePath))
            {
                FileInfo fileInfo = new FileInfo(filePath);

                if (!fileInfo.Exists)
                    Directory.CreateDirectory(filePath);

                using (StreamWriter writer = new StreamWriter(filePath + logFile, true))
                {
                    writer.WriteLine("IpAddress :" + ipAddress + "<br/>" + Environment.NewLine +
                       "" + Environment.NewLine + "Date :" + DateTime.Now.ToString());
                    writer.WriteLine(Environment.NewLine + "-----------------------------------------------------------------------------" + Environment.NewLine);
                }
            }