private void UpdateBackground(FrameworkElement frameworkElement) { var headerItem = frameworkElement.GetFirstAncestorOfType<ListViewHeaderItem>(); if (headerItem == null) return; var viewModel = (TimesByDay) frameworkElement.DataContext; if (viewModel.Day.DayOfWeek == DayOfWeek.Saturday) { headerItem.Style = (Style)this.Resources["SaturdayListViewHeaderItemStyle"]; } else if (viewModel.Day.DayOfWeek == DayOfWeek.Sunday) { headerItem.Style = (Style)this.Resources["SundayListViewHeaderItemStyle"]; } else { headerItem.Style = (Style)this.Resources["DefaultListViewHeaderItemStyle"]; } }