/// <summary>
        /// When the selected product changes, in load the prices(related to the selected product) the "SelectedProductPricesListBox" listbox
        /// Displays(by default) the price that has true for "CurrentlyActivePrice" property
        /// </summary>
        private void ProductsListBox_SelectedIndexChanged(object sender, EventArgs e)
        {
            SelectedProductPriceList = InitializeSelectedProductPriceList((ProductModel)ProductsListBox.SelectedItem);
            SalesPriceModel selectedPrice = new SalesPriceModel();

            if (SelectedProductPriceList != null)
            {
                selectedPrice = SelectedProductPriceList.Where(p => p.CurrentlyActivePrice == true).FirstOrDefault();
            }

            PriceTextBox.Text   = selectedPrice == null ? "" : selectedPrice.SalesPrice.ToString();
            lastSelectedProduct = (ProductModel)ProductsListBox.SelectedItem;
            IsCurrentlyActivePriceCheckBox.Checked = selectedPrice == null ? false : selectedPrice.CurrentlyActivePrice;
        }
        /// <summary>
        /// Imitializes the Price List related to the selected product
        /// </summary>
        private List <SalesPriceModel> InitializeSelectedProductPriceList(ProductModel selectedProduct)
        {
            InitializePriceList();
            if (selectedProduct != null)
            {
                SelectedProductPriceList = RMS_Logic.SalesPriceLogic.GetSelectedProductPrices(selectedProduct, PriceList_All);
            }

            SelectedProductPricesListBox.DataSource    = null;
            SelectedProductPricesListBox.DisplayMember = "SalesPrice";
            SelectedProductPricesListBox.DataSource    = SelectedProductPriceList;

            if (SelectedProductPriceList != null)
            {
                SelectedProductPricesListBox.SelectedItem = SelectedProductPriceList.Where(c => c.CurrentlyActivePrice == true)
                                                            .FirstOrDefault() ?? null;
            }

            return(SelectedProductPriceList);
        }