class LogHelper    {        string logFile = "";        /// <summary>        /// 不带参数的构造函数        /// </summary>        public LogHelper()        {        }        /// <summary>        /// 带参数的构造函数        /// </summary>        /// <param name="logFile"></param>        public LogHelper(string logFile)        {            this.logFile = logFile;        }        /// <summary>        /// 追加一条信息        /// </summary>        /// <param name="text"></param>        public void Write(string text)        {            using (StreamWriter sw = new StreamWriter(logFile, true, Encoding.UTF8))            {                sw.Write(DateTime.Now.ToString("[yyyy-MM-dd HH:mm:ss] ") + text);            }        }        /// <summary>        /// 追加一条信息        /// </summary>        /// <param name="logFile"></param>        /// <param name="text"></param>        public void Write(string logFile, string text)        {            using (StreamWriter sw = new StreamWriter(logFile, true, Encoding.UTF8))            {                sw.Write(DateTime.Now.ToString("[yyyy-MM-dd HH:mm:ss] ") + text);            }        }        /// <summary>        /// 追加一行信息        /// </summary>        /// <param name="text"></param>        public void WriteLine(string text)        {            text += "\r\n";            using (StreamWriter sw = new StreamWriter(logFile, true, Encoding.UTF8))            {                sw.Write(DateTime.Now.ToString("[yyyy-MM-dd HH:mm:ss] ") + text);            }        }        /// <summary>        /// 追加一行信息        /// </summary>        /// <param name="logFile"></param>        /// <param name="text"></param>        public void WriteLine(string logFile, string text)        {            text += "\r\n";            using (StreamWriter sw = new StreamWriter(logFile, true, Encoding.UTF8))            {                sw.Write(DateTime.Now.ToString("[yyyy-MM-dd HH:mm:ss] ") + text);            }        }    }