public IDisposable TryObserve(object source, IEventListener listener)
{
if (_isDataContext)
{
return(WeakEventManager.AddBindingContextListener(BindingServiceProvider.ContextManager.GetBindingContext(source), listener, true));
}
if (_memberEvent == null)
{
if (_isDynamic)
{
return(((IDynamicObject)source).TryObserve(_path, listener));
}
return(_indexerAttachedBindingMember?.TryObserve(source, listener));
}
return(_memberEvent.SetSingleValue(source, listener) as IDisposable);
}
private void Update(object source)
{
if (_parentContext != null)
{
WeakEventManager.RemoveBindingContextListener(_parentContext, this);
}
if (source == null)
{
_parentContext = null;
}
else
{
_parentContext = GetParentBindingContext(source);
if (_parentContext != null)
{
WeakEventManager.AddBindingContextListener(_parentContext, this, false);
}
}
}