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