/// <summary>
/// Construct a new instance of ObjectView using the supplied IObjectViewData and event data source.
/// </summary>
/// <param name="viewData">
/// Object that maintains the underlying bound list,
/// and specifies the operations allowed on that list.
/// </param>
/// <param name="eventDataSource">
/// Event source to "attach" to in order to listen to collection and item changes.
/// </param>
internal ObjectView(IObjectViewData <TElement> viewData, object eventDataSource)
{
_viewData = viewData;
_listener = new ObjectViewListener(this, (IList)_viewData.List, eventDataSource);
}
public ListChangedEventArgs OnCollectionChanged(object sender, CollectionChangeEventArgs e, ObjectViewListener listener)
{
ListChangedEventArgs changeArgs = null;
switch (e.Action)
{
case CollectionChangeAction.Remove:
// An Entity is being removed from entity collection, remove it from list.
if (e.Element is TViewElement)
{
TViewElement removedItem = (TViewElement)e.Element;
int oldIndex = _bindingList.IndexOf(removedItem);
if (oldIndex != -1)
{
_bindingList.Remove(removedItem);
// Unhook from events of removed entity.
listener.UnregisterEntityEvents(removedItem);
changeArgs = new ListChangedEventArgs(ListChangedType.ItemDeleted, oldIndex /* newIndex*/, -1 /* oldIndex*/);
}
}
break;
case CollectionChangeAction.Add:
// Add the entity to our list.
if (e.Element is TViewElement)
{
// Do not process Add events that fire as a result of committing an item to the entity collection.
if (!_itemCommitPending)
{
TViewElement addedItem = (TViewElement)e.Element;
_bindingList.Add(addedItem);
// Register to its events.
listener.RegisterEntityEvents(addedItem);
changeArgs = new ListChangedEventArgs(ListChangedType.ItemAdded, _bindingList.Count - 1 /* newIndex*/, -1 /* oldIndex*/);
}
}
break;
case CollectionChangeAction.Refresh:
foreach (TViewElement entity in _bindingList)
{
listener.UnregisterEntityEvents(entity);
}
_bindingList.Clear();
foreach (TViewElement entity in _entityCollection.GetInternalEnumerable())
{
_bindingList.Add(entity);
listener.RegisterEntityEvents(entity);
}
changeArgs = new ListChangedEventArgs(ListChangedType.Reset, -1 /*newIndex*/, -1 /*oldIndex*/);
break;
}
return(changeArgs);
}
public ListChangedEventArgs OnCollectionChanged(object sender, CollectionChangeEventArgs e, ObjectViewListener listener)
{
ListChangedEventArgs changeArgs = null;
// Since event is coming from cache and it might be shared amoung different queries
// we have to check to see if correct event is being handled.
if (e.Element.GetType().IsAssignableFrom(typeof(TElement)) &&
_bindingList.Contains((TElement)(e.Element)))
{
TElement item = (TElement)e.Element;
int itemIndex = _bindingList.IndexOf(item);
if (itemIndex >= 0) // Ignore entities that we don't know about.
{
// Only process "remove" events.
Debug.Assert(e.Action != CollectionChangeAction.Refresh, "Cache should never fire with refresh, it does not have clear");
if (e.Action == CollectionChangeAction.Remove)
{
_bindingList.Remove(item);
listener.UnregisterEntityEvents(item);
changeArgs = new ListChangedEventArgs(ListChangedType.ItemDeleted, itemIndex /* newIndex*/, -1 /* oldIndex*/);
}
}
}
return(changeArgs);
}
