private void DeletSweetnessTypeButton_Click(object sender, EventArgs e) { var selectedRows = SweetnessTable.SelectedRows; foreach (DataGridViewRow row in selectedRows) { int id = Convert.ToInt32(row.Cells[0].Value); SweetnessManager.DeleteData(id); SweetnessDegree local = SweetnessList.Find(x => x.Id == id); SweetnessList.Remove(local); } UpdateSweetnessTypeTable(); }