public DateTimePartGroupBehavior(DateTimePartGroup dateTimePartGroup, int step) { _dateTimePartGroup = dateTimePartGroup; this.step = step; dpDesc = DependencyPropertyDescriptor.FromProperty(DateTimePartGroup.ValueProperty, typeof(DateTimePartGroup)); _dateTimePartGroup.Unloaded += _dateTimePartGroup_Unloaded; _dateTimePartGroup.Loaded += _dateTimePartGroup_Loaded; }