private void btn_deluser_Click(object sender, EventArgs e) //Button delete user
        {
            int           i  = grid_results_adm.CurrentRow.Index;
            string        id = grid_results_adm["UserID", i].Value.ToString();
            BibliotechDAL bd = new BibliotechDAL();
            int           s  = bd.UserNbrOfLoans(id);

            if (s == 0)
            {
                bd.DeleteUser(id);
                FillViewUsers();
            }
            else
            {
                MessageBox.Show("Går ej att radera, användaren har lån");
            }
        }