Inheritance in WPF application --
Create a window with all possible controls and functions which can be act as base form.
then save it as template.
Next time when u create a new form the saved template will appear on items.
Create Window -> save it as template(File->export to template)-> create new window by selecting the template from items.
I used it in my applications and it is working.
HOPE this will be helpful.
If any new way(easy way), please reply.