/// <summary>
/// Weeks the of year.
/// </summary>
/// <param name="datetime">The datetime.</param>
/// <param name="weekRule">The weekRule.</param>
/// <param name="firstDayOfWeek">The first day of week.</param>
/// <returns></returns>
public static int WeekOfYear(this DateTime datetime, System.Globalization.CalendarWeekRule weekRule, DayOfWeek firstDayOfWeek)
{
var currentCulture = System.Globalization.CultureInfo.CurrentCulture;
return(currentCulture.Calendar.GetWeekOfYear(datetime, weekRule, firstDayOfWeek));
}
