public void ResetListeners(int startIndex, DataSourceChangedEventHandler subscriber)
{
// Note: Resetting the TerminalNode is not supported, and never needed.
for (int nPtr = startIndex; nPtr < Count - 1; nPtr++)
{
this[nPtr].Reset(subscriber);
}
}
public void Reset(DataSourceChangedEventHandler subscriber = null)
{
if (subscriber != null)
{
Unsubscribe(subscriber);
}
if (SourceKind != SourceKindEnum.Empty && SourceKind != SourceKindEnum.TerminalNode && Status.IsWatching())
{
object data = Data;
if (data != null)
{
RemoveSubscriptions(data);
}
}
}
public bool Unsubscribe(DataSourceChangedEventHandler subscriber)
{
if (DataSourceChanged == null)
{
return(false); // It's not there.
}
else
{
Delegate[] subscriberList = DataSourceChanged.GetInvocationList();
if (subscriberList.FirstOrDefault((x) => x == (Delegate)subscriber) == null)
{
return(false); // Not there.
}
else
{
DataSourceChanged -= subscriber;
return(true); // We removed it.
}
}
}
public bool Subscribe(DataSourceChangedEventHandler subscriber)
{
if (DataSourceChanged == null)
{
DataSourceChanged = subscriber;
return(true); // We added it.
}
else
{
Delegate[] subscriberList = DataSourceChanged.GetInvocationList();
if (subscriberList.FirstOrDefault((x) => x == (Delegate)subscriber) == null)
{
DataSourceChanged += subscriber;
return(true); // We added it.
}
else
{
return(false); // Already there.
}
}
}
/// <summary>
///
/// </summary>
/// <param name="pathListeners"></param>
/// <param name="index"></param>
/// <param name="newListenerProvider"></param>
/// <param name="subscriber"></param>
/// <param name="newListener"></param>
/// <returns>True if the path listener is ready to start listening to property and/or collection change events.</returns>
public ObservableSourceStatusEnum ReplaceListener(int index, ref ObservableSourceProvider newListenerProvider,
DataSourceChangedEventHandler subscriber, out ObservableSource newListener)
{
if (index == Count - 1)
{
System.Diagnostics.Debug.Assert(index != Count - 1,
"We are replacing the terminal listener. This is not good.");
}
ObservableSource oldListener = this[index];
if (newListenerProvider != null)
{
newListener = newListenerProvider.CreateObservableSource(); newListenerProvider = null;
}
else
{
newListener = null;
}
bool wasListening = oldListener?.IsListeningForNewDC == true;
if (newListener?.IsListeningForNewDC != true)
{
// The new ObservableSource is not responding to any change events.
if (index == 0)
{
System.Diagnostics.Debug.WriteLine("The Source Root is not listening.");
}
else if (wasListening)
{
System.Diagnostics.Debug.WriteLine($"The ObservableSource at node {index} is no longer listening to any change events.");
}
}
if (oldListener != null)
{
#if DEBUG
bool wasRemoved = oldListener.Unsubscribe(subscriber);
System.Diagnostics.Debug.Assert(wasListening == wasRemoved, "Was Listening does not agree with WasRemoved.");
// Remove PropertyChanged or CollectionChanged event handlers, if any.
oldListener.Reset();
#else
// Remove all event handlers.
oldListener.Reset(subscriber);
#endif
}
if (newListener == null)
{
// It is the caller's responsibility to cleanup the dependent nodes.
return(ObservableSourceStatusEnum.NoType);
}
if (newListener.IsListeningForNewDC)
{
bool isListening = newListener.Subscribe(subscriber);
System.Diagnostics.Debug.Assert(isListening, "Subscriber was already present, but should not have been.");
isListening = newListener.IsListeningForNewDC;
}
this[index] = newListener;
#if DEBUG
bool hasType = newListener.GetHasTypeAndHasData(out bool hasData);
#endif
// The new path listener is ready to start monitoring Property and/or Collection Changed events if
// it still has a reference to the object that will be monitored.
return(newListener.Status);
}
