public static DateTime CalculateDateTime(this DateTime datetime, DOWEnum dayOfWeek, bool IsEOD) =>
(IsEOD) ?
datetime.Date.AddDays((int)dayOfWeek).AddHours(23).AddMinutes(59).AddSeconds(59)
:
datetime.Date.AddDays((int)dayOfWeek).AddHours(0).AddMinutes(0).AddSeconds(0);
private DateTime CalcDateTime(int week, DOWEnum dow, bool eod = false) =>
(eod ?
ClassStartDay.Date.AddHours(23).AddMinutes(59).AddSeconds(59)
: ClassStartDay.Date.AddHours(0).AddMinutes(0).AddSeconds(0))
.AddDays((week - 1) * 7)
.AddDays(((int)dow < 0) ? 0 : (int)dow);