what's an example of using the WPF validation framework to bubble up validation up the tree?

I'm reading with WPF part of the benefit of the validation based on binding framework is that validation events might bubble up the tree so to speak.

What would be an example of where this would be useful? Just trying to underst开发者_如何学Goand.

You might be interested in the BookLibrary sample application of the WPF Application Framework (WAF). It shows how to use the bubbling validation event in WPF to be notified when any of the child control gets invalid. This is used to disable the Save button.