I haven't done exactly that. However, you can look at the ProjectList form in PTWpf to see an example of using data binding to bind a factory parameter to a control property. Well, actually the reverse, the control binds its property to the parameter, but the result is what you want. However, that technique does (I believe) rely on the control's property value actually changing to trigger the process.
That technique, btw, is exactly the same as if you use the ObjectDataProvider - I originally got that bit of XAML from an ODP example.
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