// Add many of one item
public void Add(InventoryItem inventoryItem, int quantity)
{
for (int i = 0; i < quantity; i++)
{
inventoryItem.Id = i + _items.Count();
_items.Add(inventoryItem);
}
}
// Add one of one item
public void Add(InventoryItem inventoryItem)
{
inventoryItem.Id = _items.Count();
_items.Add(inventoryItem);
}