public static IDisposable ForEachItem <T>(
this IReadOnlyPerspexList <T> collection,
Action <T> added,
Action <T> removed)
{
NotifyCollectionChangedEventHandler handler = (_, e) =>
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
foreach (T i in e.NewItems)
{
added(i);
}
break;
case NotifyCollectionChangedAction.Replace:
foreach (T i in e.OldItems)
{
removed(i);
}
foreach (T i in e.NewItems)
{
added(i);
}
break;
case NotifyCollectionChangedAction.Remove:
foreach (T i in e.OldItems)
{
removed(i);
}
break;
}
};
foreach (T i in collection)
{
added(i);
}
collection.CollectionChanged += handler;
return(Disposable.Create(() => collection.CollectionChanged -= handler));
}
public static IDisposable TrackItemPropertyChanged <T>(
this IReadOnlyPerspexList <T> collection,
Action <Tuple <object, PropertyChangedEventArgs> > callback)
{
List <INotifyPropertyChanged> tracked = new List <INotifyPropertyChanged>();
PropertyChangedEventHandler handler = (s, e) =>
{
callback(Tuple.Create(s, e));
};
collection.ForEachItem(
x =>
{
var inpc = x as INotifyPropertyChanged;
if (inpc != null)
{
inpc.PropertyChanged += handler;
tracked.Add(inpc);
}
},
x =>
{
var inpc = x as INotifyPropertyChanged;
if (inpc != null)
{
inpc.PropertyChanged -= handler;
tracked.Remove(inpc);
}
});
return(Disposable.Create(() =>
{
foreach (var i in tracked)
{
i.PropertyChanged -= handler;
}
}));
}
