c#數據存入文件通用函數

        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());
            }
            
        }