WorkHourInfo can take strings as parameters, and handle datetime too.

WorkHourInfo.cs

public class WorkHourInfo
    {
        public string dayOfWeek { get; set; }
        public DateTime? startTime { get; set; }
        public DateTime? endTime { get; set; }
        public string start
        {
            get
            {
                return startTime == null ? "closed" : Convert.ToDateTime(startTime).ToShortTimeString();
            }
        }
        public string end
        {
            get
            {
                return endTime == null ? "closed" : Convert.ToDateTime(endTime).ToShortTimeString();
            }
        }
        public bool closed
        {
            get
            {
                return (startTime == null) && (endTime == null);
            }
        }
        public string workHrs
        {
            set
            {
                this.setWorkHours(value);
            }
        }

        public WorkHourInfo() { }

        public WorkHourInfo(string start, string end, string dayOfWeek = null)
        {
            this.startTime = DateTime.Parse(start);
            this.endTime = DateTime.Parse(end);
            this.dayOfWeek = dayOfWeek;
        }

        public WorkHourInfo(DateTime start, DateTime end, string dayOfWeek = null)
        {
            this.startTime = start;
            this.endTime = start;
            this.dayOfWeek = dayOfWeek;
        }

        /// <summary>
        /// Expects Format: "Monday:09.00AM - 08.30PM"
        /// </summary>
        /// <param name="dbString"></param>
        public WorkHourInfo(string dbString)
        {
            this.setWorkHours(dbString);
        }

        private void setWorkHours(string dbString)
        {
            if (String.IsNullOrEmpty(dbString)) return;
            string[] splits = dbString.Split(':');
            this.dayOfWeek = WeekDay.GetWeekDay(splits.FirstOrDefault());
            if (splits.LastOrDefault()?.ToLower() != "closed")
            {
                string[] times = splits.LastOrDefault()?.Replace(".", ":").Split('-');
                this.startTime = DateTime.Parse(times.FirstOrDefault()?.Trim());
                this.endTime = DateTime.Parse(times.LastOrDefault()?.Trim());
            }
        }

        public class WeekDay
        {
            public const string Monday = "Monday";
            public const string Tuesday = "Tuesday";
            public const string Wednesday = "Wednesday";
            public const string Thursday = "Thursday";
            public const string Friday = "Friday";
            public const string Saturday = "Saturday";
            public const string Sunday = "Sunday";

            public static string[] GetWeekDays()
            {
                return new string[]
                {
                    Sunday,
                    Monday,
                    Tuesday,
                    Wednesday,
                    Thursday,
                    Friday,
                    Saturday
                };
            }

            public static string GetWeekDay(string partialWeekDay) //some week days are mispelled ... this fixes that, i guess
            {
                return GetWeekDays().First((day) =>
                {
                    return day.ToLower().Substring(0, 3) == partialWeekDay.ToLower().Substring(0, 3);
                });
            }
        }
    }