public bool Update(ShoppingListItem item)
{
if (item == null)
{
throw new ArgumentNullException("item can not be null");
}
int index = shoppingList.FindIndex(p => p.Name == item.Name);
if (index == -1)
{
return(false);
}
shoppingList.RemoveAt(index);
shoppingList.Add(item);
return(true);
}
public ShoppingListItem Add(ShoppingListItem item)
{
if (item == null)
{
throw new ArgumentNullException("shopping list item");
}
int index = shoppingList.FindIndex(i => i.Name == item.Name);
if (index != -1)
{
throw new Exception("an item with the same name is already in the list");
}
shoppingList.Add(item);
return(item);
}