private static IObservable <T> ObserveFullPropertyPathCore <TNotifier, TProperty, T>(this TNotifier source, NotifyingPath <TNotifier, TProperty> notifyingPath, Func <object?, PropertyChangedEventArgs, T> create, bool signalInitial = true)
where TNotifier : class, INotifyPropertyChanged
{
if (signalInitial)
{
return(Observable.Return(
create(
notifyingPath.SourceAndValue(source).Source,
CachedEventArgs.GetOrCreatePropertyChangedEventArgs(string.Empty)))
.Concat(source.ObserveFullPropertyPathCore(notifyingPath, create, signalInitial: false)));
}
return(Observable.Create <T>(
o =>
{
var tracker = notifyingPath.CreateTracker(source);
void Handler(object sender, PropertyChangedEventArgs e) => o.OnNext(create(sender, e));
foreach (var propertyTracker in tracker)
{
propertyTracker.TrackedPropertyChanged += Handler;
}
return Disposable.Create(
() =>
{
foreach (var propertyTracker in tracker)
{
propertyTracker.TrackedPropertyChanged -= Handler;
}
tracker.Dispose();
});
}));
}
private static IObservable <T> ObservePropertyChangedCore <TNotifier, TProperty, T>(
this TNotifier source,
NotifyingPath <TNotifier, TProperty> notifyingPath,
Func <object, PropertyChangedEventArgs, T> create,
bool signalInitial = true)
where TNotifier : class, INotifyPropertyChanged
{
if (signalInitial)
{
return(Observable.Return(
create(
notifyingPath.SourceAndValue(source).Source,
CachedEventArgs.GetOrCreatePropertyChangedEventArgs(string.Empty)))
.Concat(source.ObservePropertyChangedCore(notifyingPath, create, signalInitial: false)));
}
if (notifyingPath.Count > 1)
{
return(Observable.Create <T>(
o =>
{
var tracker = notifyingPath.CreateTracker(source);
void Handler(IPropertyTracker _, object sender, PropertyChangedEventArgs e, SourceAndValue <INotifyPropertyChanged, TProperty> __) => o.OnNext(create(sender, e));
tracker.TrackedPropertyChanged += Handler;
return new CompositeDisposable(2)
{
tracker,
Disposable.Create(() => tracker.TrackedPropertyChanged -= Handler),
};
}));
}
return(ObservePropertyChangedCore(source, notifyingPath.Last.Property.Name, create, signalInitial: false));
}
private static IObservable <T> ObserveValueCore <TNotifier, TProperty, T>(
this TNotifier source,
NotifyingPath <TNotifier, TProperty> notifyingPath,
Func <object?, PropertyChangedEventArgs, Maybe <TProperty>, T> create,
bool signalInitial = true)
where TNotifier : class, INotifyPropertyChanged
{
if (signalInitial)
{
return(Observable.Defer(
() =>
{
var sourceAndValue = notifyingPath.SourceAndValue(source);
return Observable.Return(
create(
sourceAndValue.Source,
CachedEventArgs.GetOrCreatePropertyChangedEventArgs(string.Empty),
sourceAndValue.Value));
})
.Concat(source.ObserveValueCore(notifyingPath, create, signalInitial: false)));
}
if (notifyingPath.Count > 1)
{
return(Observable.Create <T>(
o =>
{
var tracker = notifyingPath.CreateTracker(source);
tracker.TrackedPropertyChanged += Handler;
return new CompositeDisposable(2)
{
tracker,
Disposable.Create(() => tracker.TrackedPropertyChanged -= Handler),
};
void Handler(IPropertyTracker _, object sender, PropertyChangedEventArgs args, SourceAndValue <INotifyPropertyChanged?, TProperty> sourceAndValue)
{
o.OnNext(create(sender, args, sourceAndValue.Value));
}
}));
}
return(Observable.Create <T>(
o =>
{
void Handler(object sender, PropertyChangedEventArgs e)
{
if (e.IsMatch(notifyingPath.Last.Property))
{
var value = notifyingPath.Last.GetMaybe(sender);
o.OnNext(create(sender, e, value));
}
}
source.PropertyChanged += Handler;
return Disposable.Create(() => source.PropertyChanged -= Handler);
}));
}
