public List <Rayon> GetRayonParSecteur(int numS)
        {
            List <Rayon> mesRayons = new List <Rayon>();

            cmd = new MySqlCommand("select numr, nomr from rayon where numsecteur = " + numS, cnx);
            dr  = cmd.ExecuteReader();
            while (dr.Read())
            {
                Rayon uneCateg = new Rayon(Convert.ToInt16(dr[0].ToString()), dr[1].ToString());
                mesRayons.Add(uneCateg);
            }
            dr.Close();
            return(mesRayons);
        }
        public List <Rayon> GetAllRayons()
        {
            List <Rayon> mesRayons = new List <Rayon>();

            cmd = new MySqlCommand("select numr, nomr from rayon", cnx);
            dr  = cmd.ExecuteReader();
            while (dr.Read())
            {
                Rayon unRayon = new Rayon(Convert.ToInt16(dr[0].ToString()), dr[1].ToString());
                mesRayons.Add(unRayon);
            }
            dr.Close();
            return(mesRayons);
        }