public PartialViewResult SelectInventory(int requestNumber)
        {
            IEnumerable <InventoryModel> inventoryList = null;

            if (requestNumber < 0)
            {
                inventoryList = _inventoryProvider.GetAllData();
            }
            else
            {
                inventoryList = _inventoryProvider.GetInventoryNotInRequest(requestNumber);
            }
            if (inventoryList != null)
            {
                return(PartialView(inventoryList));
            }
            else
            {
                return(null);
            }
        }