private void UpdateShoppingList(Inventory inventory)
        {
            JourListDMContainer dm = new JourListDMContainer();
            var inv = dm.Inventories.Single(z=>z.Id == inventory.Id);
            bool needmore, needlist;
            // deal with shopping list if necessary
            needmore = inv.OnHand < inv.RestockThreshold;
            needlist = inv.ShoppingList == null;
            if (needmore)
            {
                if (needlist)
                {
                    // Createlist
                    ShoppingList list = new ShoppingList();

                    do { list.Id = Guid.NewGuid(); }
                    while (dm.ShoppingLists.Count(z => z.Id == list.Id) > 0);
                    dm.AddToShoppingLists(list);
                    inv.ShoppingList = list;
                }
                var log = inv.InventoryLogs.Where(z => z.UnitId == inv.Unit.Id);
                if (log.Count() > 0)
                {
                    double sze = (from a in log group a by a.Size into s orderby s.Count() descending select s).First().First().Size;
                    inv.ShoppingList.SizeNeeded = sze;
                    inv.ShoppingList.QuantityNeeded = Math.Round((inv.RequiredQuantity - inv.OnHand) / sze, MidpointRounding.AwayFromZero);
                }
                else
                {
                    inv.ShoppingList.SizeNeeded = (inv.RequiredQuantity - inv.OnHand);
                    inv.ShoppingList.QuantityNeeded = 1;
                }
            }
            else if (!needlist)
                // Remove the item from the shoppinglist
                dm.ShoppingLists.DeleteObject(dm.Inventories.First(z => z.ShoppingList.Id == inv.ShoppingList.Id).ShoppingList);

            dm.SaveChanges();
        }