private void DecreaseButtonClick(object sender)
        {
            PackeageViewModel packeage = (PackeageViewModel)sender;

            if (packeage.Quantity == 1)
            {
                SelectedList.Remove(packeage);
            }
            else
            {
                packeage.Quantity--;
            }
            GridLoad();
        }
 private float TeacherPriceCalculate(int studentCount, PackeageViewModel model)
 {
     return(model.Model.Money * studentCount);
 }