private void HuyDoiVe_Load(object sender, EventArgs e)
 {
     //reset form
     txtTen.Clear();
     ntxtCMND.Clear();
     DynamicCBOXQueQuan.ResetText();
     ntxtSDT.Clear();
     TextBoxGiaTien.Clear();
 }
        private void DatVe_Load(object sender, EventArgs e)
        {
            GetLoTrinhVe(); //-----><-------
            GetInfoVe();    //-----><-------

            //reset form
            txtTen.Clear();
            ntxtCMND.Clear();
            DynamicCBOXQueQuan.ResetText();
            ntxtSDT.Clear();
            TextBoxGiaTien.Clear();
        }