c#数据存入文件通用函数

        private void writelog(String str)        {            FileStream logFile;            try            {                string logStr = Directory.GetCurrentDirectory() + "\\log.txt";                if (!File.Exists(logStr))                {                    logFile = new FileStream("log.txt", FileMode.CreateNew);                }                else                {                    logFile = new FileStream("log.txt", FileMode.Append);                }                StreamWriter sw = new StreamWriter(logFile);                sw.WriteLine(str);                sw.Close();                logFile.Close();            }            catch (Exception ex)            {                MessageBox.Show(ex.ToString());            }                    }