// Change for non-preferred codes. private void grid_CellValueChanged(object sender, DataGridViewCellEventArgs e) { if (!ignoreCellChanges) { string newValue = grid[e.ColumnIndex, e.RowIndex].FormattedValue.ToString(); string reason; QueryEvent.IsPreferredControlCode(eventDB, newValue, out reason); if (reason != null) { ((MainFrame)Owner).WarningMessage(reason); } } }