void update()
        {
            succes_update = false;
            OleDbConnection connect = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data source=soft.accdb;");
            connect.Open();
            OleDbCommand command = new OleDbCommand();
            command.Connection = connect;
            command.CommandText = "update query1 SET nume=@nume, autor=@autor, nrnreg=@nrneg, tip=@tip, status=@status WHERE nume=@nume;";
            command.Parameters.AddWithValue("nume", cbCarte.SelectedText);
            command.Parameters.AddWithValue("autor", txtNumeA.Text);
            command.Parameters.AddWithValue("nrneg", txtReg.Text);
            command.Parameters.AddWithValue("tip", txtTip.Text);
            command.Parameters.AddWithValue("status", txtInchiriata.Text);
            command.ExecuteNonQuery();
            connect.Close();
            succes_update = true;
        }