private void comboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            string          value = comboBox.SelectedItem.ToString();
            ProductLocation x     = ProductLocation.Get(value);

            Console.WriteLine(x.Product_Quantity);

            if (x.Product_Code == "Empty")
            {
                listBox.Items.Clear();
                listBox.Items.Add("Product location : " + x.Product_Location);
                listBox.Items.Add("Product Code     : " + x.Product_Code);
                listBox.Items.Add("Product Quantity : " + (x.Product_Quantity));

                textBox.IsEnabled = false;
                button2.IsEnabled = false;
            }
            else
            {
                Inventory item = Inventory.Get(value);

                listBox.Items.Clear();
                listBox.Items.Add("Product : " + item.Product);
                listBox.Items.Add("Product Code : " + item.Product_Code);
                listBox.Items.Add("On Hand : " + item.On_Hand);
                listBox.Items.Add("On Order : " + item.On_Order);
                listBox.Items.Add("Reorder Level : " + item.Reorder_Level);
                listBox.Items.Add("Reorder Quantity : " + item.Reorder_Quantity);


                textBox.IsEnabled = true;
                button2.IsEnabled = true;
            }
        }