void ObservableCollectionChanged(object sender, NotifyCollectionChangingEventArgs e)
{
if (!TrackChanges)
{
return;
}
ThrowIfFromDifferentThread();
if (ExcludedTypes.Contains(sender.GetType()))
{
return;
}
if (!handlingDisconnected)
{
//we got an event through the normal path, so we're sure this object is still connected
UnsubscribeDisconnected(sender);
}
NotifyCollectionChangeMemento memento;
var key = new CollectionChangeKey(sender, e.Item, e.Action);
collectionChangeMementos.TryGetValue(key, out memento);
if (memento == null)
{
throw new NotSupportedException("CollectionChanged received without CollectionChanging");
}
memento.RememberNewValues(sender, e);
collectionChangeMementos.Remove(key);
lastCollectionChangeMemento = memento;
// exceptional situation, same object!
if (!TypeUtils.IsAggregationList(sender))
{
if (ReferenceEquals(memento.OldValue, memento.NewValue))
{
UnsubscribeDisconnected(memento.OldValue);
}
UnsubscribeDisconnected(memento.NewValue); // newly added value
}
LogCollectionChanged(memento, e);
}
protected bool Equals(CollectionChangeKey other)
{
return sender.Equals(other.sender) && item.Equals(other.item) && action == other.action;
}
void ObservableCollectionChanging(object sender, NotifyCollectionChangingEventArgs e)
{
if (!TrackChanges)
{
return;
}
ThrowIfFromDifferentThread();
if (ExcludedTypes.Contains(sender.GetType()))
{
return;
}
if (!handlingDisconnected)
{
//we got an event through the normal path, so we're sure this object is still connected
UnsubscribeDisconnected(sender);
}
// normally this will not happen unless event handlers are subscribed before undo/redo, check nevertheless
if (e.Cancel)
{
log.DebugFormat("CollectionChanging event was cancelled, skipping undo");
return;
}
FixCancelledCollectionChangingEvents();
var key = new CollectionChangeKey(sender, e.Item, e.Action);
if (collectionChangeMementos.ContainsKey(key))
{
if (handlingDisconnected)
{
return; //already received
}
throw new NotSupportedException("The same CollectionChanging event fired twice (probably two different event paths)");
}
if (restoringMemento != null)
{
if (!IsCollectionChangeEventPartOfRestore(sender, e.Index))
{
throw new InvalidOperationException("Side-effect code detected (code which changes object tree in setters or in event handlers) which is not marked with [EditAction]");
}
}
if (eventCascadeCallLevel > 1 && !handlingDisconnected)
{
if (eventCascadeCallLevel < expectedEventCascadeCallLevel)
{
expectedEventCascadeCallLevel = eventCascadeCallLevel;
}
// we must be in a side-effect
if (expectedEventCascadeCallLevel != eventCascadeCallLevel)
{
log.DebugFormat("CascadeEventLevel: {0}, ExpectedCascadeEventLevel: {1}", eventCascadeCallLevel, expectedEventCascadeCallLevel);
throw new InvalidOperationException("Side-effect code detected (code which changes object tree in setters or in event handlers) which is not marked with [EditAction]");
}
}
var memento = (NotifyCollectionChangeMemento)mementoStack.Peek();
memento.RememberOldValues(sender, e);
collectionChangeMementos[key] = memento;
if (!handlingDisconnected && !TypeUtils.IsAggregationList(sender))
{
if (restoringMemento == null)
{
HandleIfTransactional(memento.OldValue, true);
}
SubscribeDisconnected(memento.OldValue); // listen to the changes in disconnected objects
}
}
