public void RemoveListener(INotifyCollectionChanged collection, ICollectionChangedListener listener)
{
collection = collection ?? throw new ArgumentNullException(nameof(collection));
listener = listener ?? throw new ArgumentNullException(nameof(listener));
Dispatcher.UIThread.VerifyAccess();
if (_entries.TryGetValue(collection, out var entry))
{
var listeners = entry.Listeners;
for (var i = 0; i < listeners.Count; ++i)
{
if (listeners[i].TryGetTarget(out var target) && target == listener)
{
listeners.RemoveAt(i);
if (listeners.Count == 0)
{
entry.Dispose();
_entries.Remove(collection);
}
return;
}
}
}
throw new InvalidOperationException(
"Collection listener not registered for this collection/listener combination.");
}
internal void RemoveListener(ICollectionChangedListener listener)
{
if (Inner is INotifyCollectionChanged incc)
{
CollectionChangedEventManager.Instance.RemoveListener(incc, listener);
}
}
public void AddListener(INotifyCollectionChanged collection, ICollectionChangedListener listener)
{
collection = collection ?? throw new ArgumentNullException(nameof(collection));
listener = listener ?? throw new ArgumentNullException(nameof(listener));
Dispatcher.UIThread.VerifyAccess();
if (!_entries.TryGetValue(collection, out var listeners))
{
listeners = new List <WeakReference <ICollectionChangedListener> >();
_entries.Add(collection, listeners);
WeakSubscriptionManager.Subscribe(
collection,
nameof(INotifyCollectionChanged.CollectionChanged),
this);
}
foreach (var l in listeners)
{
if (l.TryGetTarget(out var target) && target == listener)
{
throw new InvalidOperationException(
"Collection listener already added for this collection/listener combination.");
}
}
listeners.Add(new WeakReference <ICollectionChangedListener>(listener));
}
/// <summary>
/// Initializes a new instance of the <see cref="WeakCollectionChangedListener"/>
/// </summary>
/// <param name="source">The source event source</param>
/// <param name="listener">The listener event listener</param>
private WeakCollectionChangedListener(
INotifyCollectionChanged source,
ICollectionChangedListener listener)
{
this._source = source;
this._source.CollectionChanged += this.SourceCollectionChanged;
this._weakListener = new WeakReference(listener);
}
internal static WeakCollectionChangedListener CreateIfNecessary(object source, ICollectionChangedListener listener)
{
if (!(source is INotifyCollectionChanged))
{
return null;
}
return new WeakCollectionChangedListener(source as INotifyCollectionChanged, listener);
}
/// <summary>
/// Initializes a new instance of the <see cref="WeakCollectionChangedListener"/>
/// </summary>
/// <param name="source">The source event source</param>
/// <param name="listener">The listener event listener</param>
private WeakCollectionChangedListener(
INotifyCollectionChanged source,
ICollectionChangedListener listener)
{
this._source = source;
this._source.CollectionChanged += this.SourceCollectionChanged;
this._weakListener = new WeakReference(listener);
}
/// <summary>
/// Creates a weak listener if the source implements <see cref="INotifyCollectionChanged"/>
/// </summary>
/// <param name="source">The source to subscribe to</param>
/// <param name="listener">The collection change listener</param>
/// <returns>A weak listener instance</returns>
public static WeakCollectionChangedListener CreateIfNecessary(
object source,
ICollectionChangedListener listener)
{
INotifyCollectionChanged notify = source as INotifyCollectionChanged;
if (notify != null)
{
return new WeakCollectionChangedListener(notify, listener);
}
return null;
}
/// <summary>
/// Creates a weak listener if the source implements <see cref="INotifyCollectionChanged"/>
/// </summary>
/// <param name="source">The source to subscribe to</param>
/// <param name="listener">The collection change listener</param>
/// <returns>A weak listener instance</returns>
public static WeakCollectionChangedListener CreateIfNecessary(
object source,
ICollectionChangedListener listener)
{
INotifyCollectionChanged notify = source as INotifyCollectionChanged;
if (notify != null)
{
return(new WeakCollectionChangedListener(notify, listener));
}
return(null);
}
/// <summary>
/// Handles collection changed events raised by the source
/// </summary>
/// <param name="sender">The source collection</param>
/// <param name="e">The event args</param>
private void SourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (this._weakListener != null)
{
ICollectionChangedListener target = this._weakListener.Target as ICollectionChangedListener;
if (target != null)
{
target.OnCollectionChanged(sender, e);
}
else
{
this.Disconnect();
}
}
}
private void SourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (this.weakListener == null)
{
return;
}
ICollectionChangedListener target = this.weakListener.Target as ICollectionChangedListener;
if (target == null)
{
this.Disconnect();
return;
}
target.OnCollectionChanged(sender, e);
}
public void AddListener(INotifyCollectionChanged collection, ICollectionChangedListener listener)
{
collection = collection ?? throw new ArgumentNullException(nameof(collection));
listener = listener ?? throw new ArgumentNullException(nameof(listener));
Dispatcher.UIThread.VerifyAccess();
if (!_entries.TryGetValue(collection, out var entry))
{
entry = new Entry(collection);
_entries.Add(collection, entry);
}
foreach (var l in entry.Listeners)
{
if (l.TryGetTarget(out var target) && target == listener)
{
throw new InvalidOperationException(
"Collection listener already added for this collection/listener combination.");
}
}
entry.Listeners.Add(new WeakReference <ICollectionChangedListener>(listener));
}
private WeakCollectionChangedListener(INotifyCollectionChanged source, ICollectionChangedListener listener)
{
this.source = source;
this.source.CollectionChanged += new NotifyCollectionChangedEventHandler(this.SourceCollectionChanged);
this.weakListener = new WeakReference(listener);
}
internal static WeakCollectionChangedListener CreateIfNecessary(object source, ICollectionChangedListener listener)
{
if (!(source is INotifyCollectionChanged))
{
return(null);
}
return(new WeakCollectionChangedListener(source as INotifyCollectionChanged, listener));
}
private WeakCollectionChangedListener(INotifyCollectionChanged source, ICollectionChangedListener listener)
{
this.source = source;
this.source.CollectionChanged += new NotifyCollectionChangedEventHandler(this.SourceCollectionChanged);
this.weakListener = new WeakReference(listener);
}
internal static WeakCollectionChangedListener CreateIfNecessary(object source, ICollectionChangedListener listener)
{
var incc = source as INotifyCollectionChanged;
if (incc != null)
{
return(new WeakCollectionChangedListener(incc, listener));
}
return(null);
}
