protected override object Evaluate()
{
Tuple <object, string> o = this.RewritePath(this.ParentBinding.Path);
this.chain = this.pathParser.Parse(o.Item1, o.Item2).ToArray();
if (this.chain != null)
{
this.AttachListeners();
PropertyPathToken last = this.chain.Last();
if (last.Type == PropertyPathTokenType.FinalValue)
{
return(last.Object);
}
else
{
return(DependencyProperty.UnsetValue);
}
}
else
{
return(null);
}
}
private void PropertyChanged(object sender, PropertyChangedEventArgs e)
{
PropertyPathToken link = this.FindLinkInChain(sender);
if (e.PropertyName == link.PropertyName)
{
this.DetachListeners();
this.Invalidate();
}
}
private void DetachListener(PropertyPathToken link)
{
IObservableDependencyObject dependencyObject = link.Object as IObservableDependencyObject;
INotifyPropertyChanged inpc = link.Object as INotifyPropertyChanged;
if (dependencyObject != null)
{
dependencyObject.RemovePropertyChangedHandler(link.PropertyName, this.DependencyPropertyChanged);
}
else if (inpc != null)
{
inpc.PropertyChanged -= this.PropertyChanged;
}
}
private void DetachListener(PropertyPathToken link)
{
IObservableDependencyObject dependencyObject = link.Object as IObservableDependencyObject;
INotifyPropertyChanged inpc = link.Object as INotifyPropertyChanged;
if (dependencyObject != null)
{
dependencyObject.RemovePropertyChangedHandler(link.PropertyName, this.DependencyPropertyChanged);
}
else if (inpc != null)
{
inpc.PropertyChanged -= this.PropertyChanged;
}
}