wpf mvvm confusion

Question

as per my understanding about mvvm is.

there is a model (entity class that also implement inotify...), view (xaml code) and some class as vm (kind of controller whi

Answer 1

why don't we simply consider and enhance code behind...

(In addition to what other have already mentioned:) because it make your code easier to read. In the code behind file, you have UI stuff that is impossible or to complicated to do in XAML. In the view model code file, you have everything related to filling your form with data.

As with all design patterns, blindly following it is not the best idea. For very small windows, MVVM might not make sense. For larger windows, MVVM forces you to make a separation of concerns, which will usually make both your code behind file and your MVVM class easier to read, to understand and to debug.