protected override void OnSourceChanged (object oldSource, object newSource)
{
base.OnSourceChanged (oldSource, newSource);
var old_do = oldSource as DependencyObject;
var new_do = newSource as DependencyObject;
if (Listener != null) {
Listener.Detach ();
}
DependencyProperty = null;
PropertyInfo = null;
if (Source == null)
return;
var type = Source.GetType ();
if (TypeName != null)
type = Application.GetComponentTypeFromName (TypeName);
if (type == null)
return;
DependencyProperty prop;
Types.Ensure (type);
if (new_do != null && DependencyProperty.TryLookup (Deployment.Current.Types.TypeToKind (type), PropertyName, out prop)) {
DependencyProperty = prop;
Listener = new WeakPropertyChangedListener (new_do, DependencyProperty, this);
}
// If there's an attached DP called 'Foo' and also a regular CLR property
// called 'Foo', we cannot use the property info from the CLR property.
// Otherwise if the CLR property declares a type converter, we could
// inadvertantly use it when we should not.
if (DependencyProperty == null || !DependencyProperty.IsAttached) {
PropertyInfo = type.GetProperty (PropertyName);
}
}
internal override void OnAttached (DependencyObject element)
{
base.OnAttached (element);
Target = (FrameworkElement) element;
if (Listener != null) {
Listener.Detach ();
Listener = null;
}
ContentControl c = Target as ContentControl;
if (TargetProperty == ContentControl.ContentProperty && c != null) {
SetsParent = c.ContentSetsParent;
c.ContentSetsParent = false;
}
// Note that Target.TemplateOwner is a weak reference - it can be GC'ed at any time
var source = Target.TemplateOwner;
if (source != null)
Listener = new WeakPropertyChangedListener (source, SourceProperty, this);
}