多种时间验证方法

            //Json方法
            HttpContext.Current.Response.ContentType = "application/json";
            DateTime[] times = BLL.Order.TimeBJManager.GetDateSchoolTime();
            //times t1 = NowDT.   (dt2); //NowDT 早于 dt2，返回 -1  
            //times t2 = NowDT.CompareTo(dt1); //NowDT 晚于 dt1，返回 1
            //times t3 = NowDT.CompareTo(dt2); //NowDT  ==  dt2，返回 0
            if (NowDT.CompareTo(times[0]) < 0 || NowDT.CompareTo(times[1]) > 0)
            {
                //当前时间 早于开始时间
                //当前时间 晚于结束时间
                string json = "{\"StartTime\":\"" + times[0] + "\",\"EndTime\": \"" + times[1] + "\"}";
                HttpContext.Current.Response.Write(json);
            }
            else
            {
                HttpContext.Current.Response.Write(null);
            }

        DataTable dt=new DataTable();
        /// <summary>
        /// 时间验证
        /// </summary>
        /// <returns></returns>
        [WebMethod]
        public void Timeyanzheng()
        {
            StringBuilder strHtml = new StringBuilder();
            DateTime NowDT = DateTime.Now;
            dt = new BLL.list.Lists().list("SYS_APPConfig", "Id,type,convert(varchar(100),StartDate,23) as StartDate,convert(varchar(100),EndDate,23) as EndDate", "").Tables[0];
           // DataSet ds = new BLL.list.Lists().list("SYS_APPConfig", "convert(varchar(100),StartDate,23) as StartDate,convert(varchar(100),EndDate,23) as EndDate", " type=‘学校端设置‘ and StartDate<‘" + NowDT + "‘ and EndDate>‘" + NowDT + "‘");
            DataRow[] dr = dt.Select("type=‘学校端设置‘ and StartDate<‘" + NowDT + "‘ and EndDate>‘" + NowDT + "‘");
            if (dr != null && dr.Length > 0)
            {
                HttpContext.Current.Response.Write("suc");
            }
            else
            {
                DataRow[] drControl = dt.Select(" type=‘学校端设置‘");
                strHtml.AppendFormat("<div><h3>学校预约时间为：{0}  ~   {1}</h3></div>", drControl[0]["StartDate"].ToString(), drControl[0]["EndDate"].ToString());
                HttpContext.Current.Response.Write(strHtml.ToString());
            }
        }