public ValueDisplayViewModel(IEventAggregator eventAggregator, IRegistryFactory registryFactory)
{
_registryFactory = registryFactory;
eventAggregator.Subscribe(this);
((ListCollectionView)CollectionViewSource.GetDefaultView(Values)).CustomSort = ValueComparer.Default;
Values.CollectionChanged += (sender, e) =>
{
void SubscribeNewItems()
{
foreach (IValueViewModel item in e.NewItems)
{
item.Deleted += ValueDeleted;
}
}
void UnsubscribeOldItems()
{
foreach (IValueViewModel item in e.OldItems)
{
item.Deleted -= ValueDeleted;
}
}
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
SubscribeNewItems();
break;
case NotifyCollectionChangedAction.Remove:
UnsubscribeOldItems();
break;
case NotifyCollectionChangedAction.Replace:
UnsubscribeOldItems();
SubscribeNewItems();
break;
case NotifyCollectionChangedAction.Reset:
Values.Apply(value => value.Deleted += ValueDeleted);
break;
}
};
}