/// <summary>
/// Gets or sets the element at the specified index.
/// </summary>
/// <param name="index">The zero-based index of the element to get or set.</param>
/// <returns>The element at the specified index.</returns>
/// <exception cref="System.ArgumentOutOfRangeException"><paramref name="index"/> is not a valid index in the list.</exception>
public T this[int index]
{
get
{
lock (gate)
{
EnsureNotDisposed();
EnsureNotFaulted();
Contract.Assume(index < list.Count);
return(list[index]);
}
}
set
{
lock (gate)
{
EnsureNotDisposed();
if (EnsureNotStopped())
{
Contract.Assume(index < list.Count);
T previous = list[index];
list[index] = value;
subject.OnNext(CollectionNotification.CreateOnReplaced(previous, value));
}
}
}
}
private void SetInternal(KeyValuePair <TKey, TValue> newPair)
{
if (dictionary.Contains(newPair.Key))
{
int index = dictionary.IndexOf(newPair.Key);
Contract.Assume(index >= 0);
var oldPair = dictionary[index];
dictionary[index] = newPair;
OnPropertyChanged(new PropertyChangedEventArgs("Values"));
OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
#if !PORT_40
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, newPair, oldPair, index));
#endif
subject.OnNext(CollectionNotification.CreateOnReplaced(oldPair, newPair));
}
else
{
AddInternal(newPair);
}
}
/// <summary>
/// Converts <see cref="INotifyCollectionChanged.CollectionChanged"/> events into an observable sequence of <see cref="CollectionNotification{T}"/>.
/// </summary>
/// <typeparam name="T">The object that provides notification information.</typeparam>
/// <param name="source">An implementation of <see cref="INotifyCollectionChanged"/> that raises events when a collection changes.</param>
/// <remarks>
/// An <see cref="NotifyCollectionChangedAction.Add"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnAdded"/> notifications.
/// A <see cref="NotifyCollectionChangedAction.Remove"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnRemoved"/> notifications.
/// A <see cref="NotifyCollectionChangedAction.Move"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnReplaced"/> notifications
/// where <see cref="CollectionNotification{T}.Value"/> and <see cref="CollectionNotification{T}.ReplacedValue"/> refer to the same value.
/// A <see cref="NotifyCollectionChangedAction.Replace"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnReplaced"/> notifications.
/// A <see cref="NotifyCollectionChangedAction.Reset"/> event is projected into a single <see cref="CollectionNotificationKind.OnCleared"/> notification.
/// </remarks>
/// <returns>An observable sequence of <see cref="CollectionNotification{T}"/> objects corresponding to raised events.</returns>
#else
/// <summary>
/// Converts <see cref="INotifyCollectionChanged.CollectionChanged"/> events into an observable sequence of <see cref="CollectionNotification{T}"/>.
/// </summary>
/// <typeparam name="T">The object that provides notification information.</typeparam>
/// <param name="source">An implementation of <see cref="INotifyCollectionChanged"/> that raises events when a collection changes.</param>
/// <remarks>
/// An <see cref="NotifyCollectionChangedAction.Add"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnAdded"/> notifications.
/// A <see cref="NotifyCollectionChangedAction.Remove"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnRemoved"/> notifications.
/// A <see cref="NotifyCollectionChangedAction.Replace"/> event is projected into zero or more <see cref="CollectionNotificationKind.OnReplaced"/> notifications.
/// A <see cref="NotifyCollectionChangedAction.Reset"/> event is projected into a single <see cref="CollectionNotificationKind.OnCleared"/> notification.
/// </remarks>
/// <returns>An observable sequence of <see cref="CollectionNotification{T}"/> objects corresponding to raised events.</returns>
#endif
public static IObservable <CollectionNotification <T> > AsCollectionNotifications <T>(this INotifyCollectionChanged source)
{
Contract.Requires(source != null);
Contract.Ensures(Contract.Result <IObservable <CollectionNotification <T> > >() != null);
return(Observable.FromEventPattern <NotifyCollectionChangedEventHandler, NotifyCollectionChangedEventArgs>(
eh => source.CollectionChanged += eh,
eh => source.CollectionChanged -= eh)
.SelectMany(e =>
{
var args = e.EventArgs;
switch (args.Action)
{
case NotifyCollectionChangedAction.Add:
return EnsureSequence <T>(args.NewItems).Select(CollectionNotification.CreateOnAdded).ToObservable();
case NotifyCollectionChangedAction.Remove:
return EnsureSequence <T>(args.OldItems).Select(CollectionNotification.CreateOnRemoved).ToObservable();
#if !SILVERLIGHT
case NotifyCollectionChangedAction.Move:
return EnsureSequence <T>(args.OldItems).Select(value => CollectionNotification.CreateOnReplaced(value, value)).ToObservable();
#endif
case NotifyCollectionChangedAction.Replace:
return EnsureSequence <T>(args.NewItems)
.Zip(
EnsureSequence <T>(args.OldItems),
(newValue, oldValue) => CollectionNotification.CreateOnReplaced(oldValue, newValue))
.ToObservable();
case NotifyCollectionChangedAction.Reset:
return Observable.Return(CollectionNotification.CreateOnCleared <T>());
default:
throw new InvalidOperationException();
}
}));
}
protected override void Main()
{
var source = new DictionarySubject <string, CustomValue>();
var monitorKeys = new[] { "A", "C", "D", "E", "F", "G" };
// PropertyChanges doesn't work on KeyValuePair because it doesn't have any property change events.
// So we must strip off the key and create a sequence of collection notifications for the values only.
using (source
.Where(
exists: _ => false,
onAdded: added => monitorKeys.Contains(added.Key),
onReplaced: (replaced, added) => monitorKeys.Contains(replaced.Key) && monitorKeys.Contains(added.Key),
onRemoved: removed => monitorKeys.Contains(removed.Key),
onCleared: () => false)
.Select(
_ => null,
added => CollectionNotification.CreateOnAdded(added.Value),
(replaced, added) => CollectionNotification.CreateOnReplaced(replaced.Value, added.Value),
removed => CollectionNotification.CreateOnRemoved(removed.Value),
() => null)
.PropertyChanges()
.Select(e => new { Object = (CustomValue)e.Sender, Property = e.EventArgs.PropertyName })
.Subscribe(value => TraceLine("Changed {0}: {1}", value.Property, value.Object)))
{
var a = new CustomValue("A");
var b = new CustomValue("B");
var c = new CustomValue("C");
source.Add(a.Name, a);
source.Add(b.Name, b);
source.Add(c.Name, c);
a.Child = new CustomValue("D");
b.Child = new CustomValue("E");
c.Child = new CustomValue("F");
a.Child.Child = new CustomValue("G");
a.Number = 1;
b.Number = 1;
c.Number = 1;
a.Child.Number = 100;
b.Child.Number = 101;
c.Child.Number = 102;
var child = a.Child;
var grandchild = child.Child;
grandchild.Number = 103;
child.Child = null;
grandchild.Number = 104;
child.Number = 105;
a.Child = null;
child.Number = 106;
source.Remove(a.Name);
a.Number = 2;
b.Number = 2;
c.Number = 2;
child.Number = 200;
b.Child.Number = 201;
c.Child.Number = 202;
grandchild.Number = 203;
source.Remove(b.Name);
source.Remove(c.Name);
a.Number = 4;
b.Number = 4;
c.Number = 4;
child.Number = 300;
b.Child.Number = 301;
c.Child.Number = 302;
grandchild.Number = 303;
}
}
