void Fillcombo()
        {
            string connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=F:\Stage_ap\BD\MontHoreb.accdb";
            conn.ConnectionString = connectionString;
            conn.Open();
            OleDbDataAdapter adapter = new OleDbDataAdapter("SELECT Code_Marche, Libelle_Marche FROM MARCHE", conn);
            DataTable dt = new DataTable();
            adapter.Fill(dt);
            cmbCodeMaPh.DataSource = dt;
            cmbCodeMaPh.DisplayMember = "Libelle_Marche";
            conn.Close();
        }