public Quantity Add(Quantity item)
{
if (item == null)
{
throw new ArgumentNullException("item");
}
item.Id = _nextId++;
quantities.Add(item);
return item;
}
public bool Update(Quantity item)
{
if (item == null)
{
throw new ArgumentNullException("item");
}
int index = quantities.FindIndex(p => p.Id == item.Id);
if (index == -1)
{
return false;
}
quantities.RemoveAt(index);
quantities.Add(item);
return true;
}
