private void Fixupsupplier(supplier previousValue) { if (previousValue != null && previousValue.product_purchase_history_master.Contains(this)) { previousValue.product_purchase_history_master.Remove(this); } if (supplier != null) { if (!supplier.product_purchase_history_master.Contains(this)) { supplier.product_purchase_history_master.Add(this); } if (supplier_id != supplier.id) { supplier_id = supplier.id; } } else if (!_settingFK) { supplier_id = null; } }