Understanding how DependencyProperty works and is implemented

The Silverlight/WPF DependencyProperty enables data binding and indicates when the property has changed in value, without implementing INotifyPropertyChanged. My question is on how does this work at the low level - how does DependencyProperty or DependencyObject perform this change notification when neither DependencyObject, DependencyProperty, nor DispatcherObject define any events. Would this have something to do with the DispatcherObject.Dispatcher property?

Dependency properties, or the开发者_如何学Go DependencyObject class, do not natively support INotifyPropertyChanged for purposes of producing notifications of changes in DependencyObject source property value for data binding operations.

This excellent clarification was taken word-for-word from:

http://msdn.microsoft.com/en-us/library/ms752914.aspx

http://msdn.microsoft.com/en-us/library/ms753358.aspx

Dependency properties are tightly integrated with the binding system internally. So instead of "notifying that the property changed", the code that sets the dependency property can call directly into the binding system and tell it to updated.

Similarly, things like inherited/attached properties can be updated on any descendant elements and/or the layout/measure/arrange can be updated. It can even tell any triggers (in Styles or ControlTemplates) to be reevaluated.

The Dispatcher isn't really related, but may be used during the process.

So in short, it's baked into WPF/Silverlight.

Well, when you register a DependencyProperty you provide a callback to be called when the value changes.

Here you have more details. I don't think anything else is public about the internals of WPF. I might be wrong.