protected override void PrepareContainerForItemOverride(DependencyObject element, object item) { DataGridContext dataGridContext = DataGridControl.GetDataGridContext(this); DataGridControl grid = (dataGridContext != null) ? dataGridContext.DataGridControl : null; base.PrepareContainerForItemOverride(element, item); if (grid != null) { GroupByItem groupByItem = ( GroupByItem )element; groupByItem.PrepareDefaultStyleKey(grid.GetView()); } }