public override nfloat GetRowHeight(NSOutlineView outlineView, NSObject item) { var height = outlineView.RowHeight; var row = outlineView.RowForItem(item); for (int i = 0; i < outlineView.ColumnCount; i++) { var cell = outlineView.GetCell(i, row); if (cell != null) { height = (nfloat)Math.Max(height, cell.CellSize.Height); } } return(height); }