void setupRx(IEnumerable <T> initialContents = null, IScheduler scheduler = null, double resetChangeThreshold = 0.3)
{
if (rxObjectsSetup)
{
return;
}
scheduler = scheduler ?? RxApp.DeferredScheduler;
_inner = _inner ?? new List <T>();
_changing = new Subject <NotifyCollectionChangedEventArgs>();
_changing.Subscribe(raiseCollectionChanging);
_changed = new Subject <NotifyCollectionChangedEventArgs>();
_changed.Subscribe(raiseCollectionChanged);
ResetChangeThreshold = resetChangeThreshold;
_beforeItemsAdded = new Lazy <Subject <T> >(() => new Subject <T>());
_itemsAdded = new Lazy <Subject <T> >(() => new Subject <T>());
_beforeItemsRemoved = new Lazy <Subject <T> >(() => new Subject <T>());
_itemsRemoved = new Lazy <Subject <T> >(() => new Subject <T>());
_itemChanging = new Lazy <Subject <IObservedChange <T, object> > >(() => new Subject <IObservedChange <T, object> >());
_itemChanged = new Lazy <Subject <IObservedChange <T, object> > >(() => new Subject <IObservedChange <T, object> >());
_beforeItemsMoved = new Lazy <Subject <IMoveInfo <T> > >(() => new Subject <IMoveInfo <T> >());
_itemsMoved = new Lazy <Subject <IMoveInfo <T> > >(() => new Subject <IMoveInfo <T> >());
// NB: We have to do this instead of initializing _inner so that
// Collection<T>'s accounting is correct
foreach (var item in initialContents ?? Enumerable.Empty <T>())
{
Add(item);
}
// NB: ObservableCollection has a Secret Handshake with WPF where
// they fire an INPC notification with the token "Item[]". Emulate
// it here
CollectionCountChanging.Select(x => new PropertyChangingEventArgs("Count")).Subscribe(this.raisePropertyChanging);
CollectionCountChanged.Select(x => new PropertyChangedEventArgs("Count")).Subscribe(this.raisePropertyChanged);
Changing.Select(x => new PropertyChangingEventArgs("Item[]")).Subscribe(this.raisePropertyChanging);
Changed.Select(x => new PropertyChangedEventArgs("Item[]")).Subscribe(this.raisePropertyChanged);
rxObjectsSetup = true;
}
void setupRx(IEnumerable <T> List = null)
{
_BeforeItemsAdded = new ScheduledSubject <T>(RxApp.DeferredScheduler);
_BeforeItemsRemoved = new ScheduledSubject <T>(RxApp.DeferredScheduler);
aboutToClear = new Subject <int>();
cleared = new Subject <int>();
if (List != null)
{
foreach (var v in List)
{
this.Add(v);
}
}
var ocChangedEvent = new Subject <NotifyCollectionChangedEventArgs>();
CollectionChanged += (o, e) => ocChangedEvent.OnNext(e);
_ItemsAdded = ocChangedEvent
.Where(x =>
x.Action == NotifyCollectionChangedAction.Add ||
x.Action == NotifyCollectionChangedAction.Replace)
.SelectMany(x =>
(x.NewItems != null ? x.NewItems.OfType <T>() : Enumerable.Empty <T>())
.ToObservable())
.Multicast(new ScheduledSubject <T>(RxApp.DeferredScheduler))
.PermaRef();
_ItemsRemoved = ocChangedEvent
.Where(x =>
x.Action == NotifyCollectionChangedAction.Remove ||
x.Action == NotifyCollectionChangedAction.Replace)
.SelectMany(x =>
(x.OldItems != null ? x.OldItems.OfType <T>() : Enumerable.Empty <T>())
.ToObservable())
.Multicast(new ScheduledSubject <T>(RxApp.DeferredScheduler))
.PermaRef();
_CollectionCountChanging = Observable.Merge(
_BeforeItemsAdded.Select(_ => this.Count),
_BeforeItemsRemoved.Select(_ => this.Count),
aboutToClear
);
_CollectionCountChanged = Observable.Merge(
_ItemsAdded.Select(_ => this.Count),
_ItemsRemoved.Select(_ => this.Count),
cleared
);
_ItemChanging = new ScheduledSubject <IObservedChange <T, object> >(RxApp.DeferredScheduler);
_ItemChanged = new ScheduledSubject <IObservedChange <T, object> >(RxApp.DeferredScheduler);
// TODO: Fix up this selector nonsense once SL/WP7 gets Covariance
_Changing = Observable.Merge(
_BeforeItemsAdded.Select <T, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = "Items", Sender = this, Value = this
}),
_BeforeItemsRemoved.Select <T, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = "Items", Sender = this, Value = this
}),
aboutToClear.Select <int, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = "Items", Sender = this, Value = this
}),
_ItemChanging.Select <IObservedChange <T, object>, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = x.PropertyName, Sender = x.Sender, Value = x.Value
}));
_Changed = Observable.Merge(
_ItemsAdded.Select <T, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = "Items", Sender = this, Value = this
}),
_ItemsRemoved.Select <T, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = "Items", Sender = this, Value = this
}),
_ItemChanged.Select <IObservedChange <T, object>, IObservedChange <object, object> >(x =>
new ObservedChange <object, object>()
{
PropertyName = x.PropertyName, Sender = x.Sender, Value = x.Value
}));
_ItemsAdded.Subscribe(x => {
this.Log().Debug("Item Added to {0:X} - {1}", this.GetHashCode(), x);
if (propertyChangeWatchers == null)
{
return;
}
addItemToPropertyTracking(x);
});
_ItemsRemoved.Subscribe(x => {
this.Log().Debug("Item removed from {0:X} - {1}", this.GetHashCode(), x);
if (propertyChangeWatchers == null || !propertyChangeWatchers.ContainsKey(x))
{
return;
}
removeItemFromPropertyTracking(x);
});
IsEmpty = CollectionCountChanged.Select(x => x == 0);
#if DEBUG
_ItemChanged.Subscribe(x =>
this.Log().Debug("Object {0} changed in collection {1:X}", x, this.GetHashCode()));
#endif
}