public static void Reset <T>(this IChangeable <T> r, IEnumerable <T> newItems) => r.Change(ItemChangedArgs.Reset(newItems, null));
public static void Update <T>(this IChangeable <T> r, T item) => r.Change(ItemChangedArgs.Update(item));
public static void Remove <T>(this IChangeable <T> r, int id) => r.Change(ItemChangedArgs.Remove <T>(id));
public static void Remove <T>(this IChangeable <T> r, T item) => r.Change(ItemChangedArgs.Remove(item));
public static void Add <T>(this IChangeable <T> r, T item) => r.Change(ItemChangedArgs.Add(item));
public void Change(ItemChangedArgs <T> args)
{
switch (args.Action)
{
case ItemChangedAction.Add:
_items.Add(args.Item.Id, args.Item);
break;
case ItemChangedAction.Remove:
if (args.Id.HasValue)
{
var id = args.Id.Value;
T removed;
if (_items.TryGetValue(id, out removed))
{
args = ItemChangedArgs.Remove(removed);
}
_items.Remove(id);
}
else
{
_items.Remove(args.Item.Id);
}
break;
case ItemChangedAction.Update:
{
T removed;
if (_items.TryGetValue(args.Item.Id, out removed))
{
args = ItemChangedArgs.Update(args.Item, removed);
}
_items[args.Item.Id] = args.Item;
}
break;
case ItemChangedAction.Reset:
{
var newItems = args.NewItems;
var oldItems = _items.Values;
var removed = Except(oldItems, newItems);
var added = Except(newItems, oldItems);
_items.Clear();
if (newItems != null)
{
foreach (var item in newItems)
{
_items[item.Id] = item;
}
}
args = ItemChangedArgs.Reset(newItems, oldItems);
}
break;
default:
throw new ArgumentException("Invalid arg.Action");
}
_Changed.OnNext(this, args);
}