public bool Update(int id, Item item)
{
if (item == null) return false;
// Don't allow the id to be changed.
item.Id = id;
bool have = _items.ContainsKey(id);
if (have) {
_items[id] = item;
}
return have;
}
// Add a unique Id and insert into the Dictionary, then return the item.
// Return null if the item cannot be added
public Item Add(Item item)
{
// Note: if we knew more about Items, we could check to see if there already was a matching item in the Dictionary.
// However, in this example we don't want to assume anything except the int Id.
if (null == item) {
return null;
}
item.Id = NextId(item);
_items.Add(item.Id, item);
return item;
}
// Generating the next index is pretty simple with an int, but this makes it easier to
// generate the next unique Id for any index type.
private int NextId(Item item)
{
return _nextId++;
}