一个简单的日志类，测试时候用

 1  class LogWriter
 2    {
 3        private static string path = Application.StartupPath + "\\log.txt";
 4        static LogWriter()
 5        {
 6
 7            if (!File.Exists(path))
 8            {
 9                FileStream fs = File.Create(path);
                fs.Close();
            }

            Log("Log Start:");
        }

        public static void Log(string str)
        {
            StreamWriter sw = File.AppendText(path);
            sw.WriteLine(DateTime.Now.ToLongTimeString() + ":    " + str);
            sw.Close();
        }

        public static void Error(string str)
        {
            StreamWriter sw = File.AppendText(path);
            sw.WriteLine(DateTime.Now.ToLongTimeString() + ":    Error   " + str);
            sw.Close();
        }
    }