/// <summary>
/// Initializes a new instance of the <see cref="DependencyPropertyListener" /> class.
/// </summary>
public DependencyPropertyListener(object source, string propertyToBind, IEventListener listener)
{
_listener = listener.ToWeakWrapper();
BindingOperations.SetBinding(this, ValueProperty,
new BindingEx
{
Path = new PropertyPath(propertyToBind),
Source = source,
Mode = BindingMode.OneWay,
#if !NETFX_CORE
#if !WINDOWS_PHONE
UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged,
#endif
#if !WINDOWSCOMMON
#if !WPF || !NET4
ValidatesOnNotifyDataErrors = false,
#endif
ValidatesOnDataErrors = false,
ValidatesOnExceptions = false,
NotifyOnValidationError = false,
#endif
#if WPF
NotifyOnSourceUpdated = false,
NotifyOnTargetUpdated = false
#endif
#endif
});
}
public void Dispose()
{
var listener = _eventListener;
var weakItem = _weakItem;
if (listener != null && !weakItem.IsEmpty)
{
_eventListener = null;
_weakItem = WeakEventListenerWrapper.Empty;
listener.Remove(weakItem, _propertyName);
}
}
static WeakEventListenerWrapper()
{
Empty = default(WeakEventListenerWrapper);
}
/// <summary>
/// Occurs on add a listener.
/// </summary>
protected override bool OnAdd(WeakEventListenerWrapper weakItem, bool withUnsubscriber, out IDisposable unsubscriber)
{
unsubscriber = null;
if (!ReferenceEquals(Listeners, Empty))
return false;
var source = _sourceRef.Target;
if (source == null)
return false;
var state = new object[] { this, weakItem, null };
string member = _eventInfo == null ? BindingContextMember : EventPrefix + _eventInfo.Name;
ServiceProvider.AttachedValueProvider.AddOrUpdate(source, member, AddSourceEventDelegate, UpdateSourceEventDelegate, state);
unsubscriber = (IDisposable)state[2];
return true;
}
private void Update(WeakEventListenerWrapper newItem, string path)
{
var references = newItem.IsEmpty
? new KeyValuePair<WeakEventListenerWrapper, string>[_listeners.Length]
: new KeyValuePair<WeakEventListenerWrapper, string>[_listeners.Length + 1];
int index = 0;
for (int i = 0; i < _listeners.Length; i++)
{
var reference = _listeners[i];
if (reference.Key.EventListener.IsAlive)
references[index++] = reference;
}
if (!newItem.IsEmpty)
{
references[index] = new KeyValuePair<WeakEventListenerWrapper, string>(newItem, path);
index++;
}
else if (index == 0)
{
//Remove event from source, if no listeners.
_listeners = Empty;
var target = (INotifyPropertyChanged)_propertyChanged.Target;
if (target != null)
{
target.PropertyChanged -= Handle;
ServiceProvider.AttachedValueProvider.Clear(target, PropertyChangedMember);
}
return;
}
if (references.Length != index)
Array.Resize(ref references, index);
_listeners = references;
}
private void Remove(WeakEventListenerWrapper weakItem)
{
lock (_propertyChanged)
{
for (int i = 0; i < _listeners.Length; i++)
{
if (ReferenceEquals(_listeners[i].Key.Source, weakItem.Source))
{
_listeners[i] = new KeyValuePair<WeakEventListenerWrapper, string>(WeakEventListenerWrapper.Empty, string.Empty);
Update(WeakEventListenerWrapper.Empty, null);
return;
}
}
}
}
private IDisposable AddInternal(WeakEventListenerWrapper weakItem, string path)
{
lock (_propertyChanged)
{
//if value was removed from another thread
if (ReferenceEquals(_listeners, Empty))
{
var source = (INotifyPropertyChanged)_propertyChanged.Target;
if (source != null)
{
var state = new object[] { this, weakItem, path, null };
ServiceProvider.AttachedValueProvider.AddOrUpdate(source, PropertyChangedMember, AddSourceEventDelegate, UpdateSourceEventDelegate, state);
return (IDisposable)state[3];
}
}
else if (_listeners.Length == 0)
_listeners = new[] { new KeyValuePair<WeakEventListenerWrapper, string>(weakItem, path) };
else
Update(weakItem, path);
}
return new Unsubscriber(this, weakItem);
}
public Unsubscriber(WeakPropertyChangedListener eventListener, WeakEventListenerWrapper weakItem)
{
_eventListener = eventListener;
_weakItem = weakItem;
}
public VisiblityObserver(View view, IEventListener handler)
: base(view, true)
{
_listenerRef = handler.ToWeakWrapper();
_oldValue = view.Visibility;
}
public SizeObserver(View view, IEventListener handler)
: base(view, false)
{
_listenerRef = handler.ToWeakWrapper();
_height = view.Height;
_width = view.Width;
}
static WeakEventListenerWrapper()
{
Empty = default(WeakEventListenerWrapper);
}
public Unsubscriber(WeakPropertyChangedListener eventListener, WeakEventListenerWrapper weakItem, string propertyName)
{
_eventListener = eventListener;
_weakItem = weakItem;
_propertyName = propertyName;
}
private void Remove(WeakEventListenerWrapper weakItem, string propertyName)
{
lock (this)
{
for (int i = 0; i < _listeners.Length; i++)
{
var pair = _listeners[i];
if (!pair.Key.IsEmpty && pair.Value == propertyName && ReferenceEquals(pair.Key.Source, weakItem.Source))
{
++_removedSize;
_listeners[i] = default(KeyValuePair<WeakEventListenerWrapper, string>);
return;
}
}
}
}
private IDisposable AddInternal(WeakEventListenerWrapper weakItem, string path)
{
lock (this)
{
if (_listeners.Length == 0)
{
_listeners = new[] { new KeyValuePair<WeakEventListenerWrapper, string>(weakItem, path) };
_size = 1;
_removedSize = 0;
}
else
{
if (_removedSize == 0)
{
if (_size == _listeners.Length)
EventListenerList.EnsureCapacity(ref _listeners, _size, _size + 1);
_listeners[_size++] = new KeyValuePair<WeakEventListenerWrapper, string>(weakItem, path);
}
else
{
for (int i = 0; i < _size; i++)
{
if (_listeners[i].Key.IsEmpty)
{
_listeners[i] = new KeyValuePair<WeakEventListenerWrapper, string>(weakItem, path);
--_removedSize;
break;
}
}
}
}
}
return new Unsubscriber(this, weakItem, path);
}
