public TransactionForm()
{
InitializeComponent();
con = new SqlConnection();
con.ConnectionString = "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=SQLdatabase;Integrated Security=True;Connect" +
" Timeout=30;Encrypt=False;TrustServerCertificate=True;ApplicationIntent=ReadWrite;MultiSubnetFailover=False";
dbc = new DBconnector();
//get the first index
int first = dbc.getFirstId("Transaction");
//get the first transaction
tr = getTransactionFromDB(first);
nId.Value = first;
//get all transactions
updateList();
//show the first transaction
fillForm();
}