/// <summary>
/// 切換上一頁按鈕事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void ClickPreviousPageButton(object sender, EventArgs e)
{
_customerPresentationModel.UpdateNowPage(_formData, _previousPageButton.Name);
SetMealButtonOption();
SetPageButtonEnable();
_pageLabel.Text = _customerPresentationModel.SetPageLabelText(_formData.nowPage, _formData.totalPage);
_addButton.Enabled = false;
_customerModel.SetSelectedMeal(new Meal(Constant.INITIAL, 0));
_mealDescriptionBox.Text = _customerModel.GetSelectedMeal()._mealDescription;
}