I just ran into a limitation with WPF that makes the current PasswordBox unusable. I must create a derive control to implement some interfaces that my UI needs.
What that said, is there another control out there that serve the same purpose and is NOT sealed? Opensource possibly?
The general approach to controls in WPF is to compose (or restyle) rather than inherit. As such, if you want to create wrapped behavior around a PasswordBox, one option is to derive a new UserControl containing a PasswordBox, then implement the interfaces on your new UserControl. If the overhead of a UserControl is too high (it shouldn't be in most cases; it's a lot lighter than the old WinForms User Control concept), you can derive from FrameworkElement directly, though this is a bit more work (have to override a few methods to forward the Arrange/Measure steps and add the PasswordBox to the visual tree.)
