Asp.net(code to write error in file)

Using System.IO
 public class CreateLogFiles
    {
        private string sLogFormat;
        private string sErrorTime;
        //Public method

        public CreateLogFiles()
        {
            sLogFormat = DateTime.Now.ToShortDateString().ToString() + "" + DateTime.Now.ToLongDateString().ToString() + "==>";
            string sYear = DateTime.Now.Year.ToString();
            string  sMonth = DateTime.Now.Month.ToString();
            string sDay = DateTime.Now.Day.ToString();
            sErrorTime = sYear + sMonth + sDay;
        }
        public void Errorlog(string sPathName, string sErrMsg, string PageName, string FunctionName)
        {
           StreamWriter sw=new StreamWriter(sPathName+sErrorTime+"-"+PageName+"-"+FunctionName,true);
            sw.WriteLine(sLogFormat+sErrMsg);
            sw.Flush();
            sw.Close();

    }

        }