public static string[] DaysInMonth(DateTime dateTime)
{
return
Enumerable.Range(1, DateTime.DaysInMonth(dateTime.Year, dateTime.Month))
.Select(
day =>
string.Format(
"{0}{1}{2}",
dateTime.Year.ToString("D4"),
dateTime.Month.ToString("D2"),
day.ToString("D2")))
.ToArray();
}