protected virtual void PrepareContainer(DataGridContext dataGridContext, object item) { if (m_isContainerPrepared) { Debug.Fail("A GroupHeaderControl can't be prepared twice, it must be cleaned before PrepareContainer is called again"); } Group group = null; DataGridContext gridContext = DataGridControl.GetDataGridContext(this); if (gridContext != null) { object dataItem = gridContext.GetItemFromContainer(this); if (dataItem != null) { group = gridContext.GetGroupFromItem(dataItem); } } this.SetGroup(group); m_itemContainerManager.Prepare(gridContext, item); m_isContainerPrepared = true; }