รบกวนสอบถามหน่อยครับ ผมจะทำ Combobox ที่ดึงข้อมูลจาก Database C#

        public void Spacimen()
        {
            MySqlConnection conn = new MySqlConnection(StrConn);
            conn.Open();
            string cmd = "SELECT * FROM t_specimentype";
            MySqlDataAdapter dAdapter = new MySqlDataAdapter(cmd, conn);
            DataSet ds = new DataSet();
            dAdapter.Fill(ds);
            dt = ds.Tables[0];
            Combobox .Items.Insert(0, "- SELECT -");
            Combobox .DataSource = dt;
            Combobox .DisplayMember = ("SpecimenType");
            Combobox .ValueMember = ("SpecimenID");
            Combobox .SelectedIndex = 0;
            conn.Close();
        }