public static HashSet <EDaysOfWeekExt> ConvertFrom(EDaysOfWeekFlags daysOfWeek)
{
HashSet <EDaysOfWeekExt> retVal = new HashSet <EDaysOfWeekExt>();
foreach (EDaysOfWeekFlags d in DaysOfWeekFlags.AsSeperateValues(daysOfWeek))
{
retVal.Add((EDaysOfWeekExt)Enum.Parse(typeof(EDaysOfWeekExt), Enum.GetName(typeof(EDaysOfWeekFlags), d)));
}
return(retVal);
}
public DateTime GetPrevious(DateTime fromDate)
{
if (this.WeekCount <= 0)
{
throw new InvalidOperationException($"Invalid Week Count property value ({this.WeekCount})");
}
if (this.DaysOfWeek == EDaysOfWeekFlags.None)
{
throw new InvalidOperationException("No days of the week selected.");
}
DateTime date = fromDate;
HashSet <EDaysOfWeekFlags> dowSet = DaysOfWeekFlags.AsSeperateValues(this.DaysOfWeek);
// move up to the next week day that is in DaysOfWeek property and subtract (WeekCount * 7) days.
while (!dowSet.Contains(DaysOfWeekFlags.ConvertFrom(date.DayOfWeek)))
{
date = date.AddDays(1);
}
return(date.AddDays(-(this.WeekCount * 7)).Date);
}