Standard Approach of Launching Dialogs/Child Windows from a WPF Application using MVVM

Question

All, I would like to know the recognised best approach/industry standard of launching [child] dialogs/windows from an WPF using the MVVM pattern. I have come across the foll

Answer 1

Purpose of using interface to implement dialogs is to make code testable. In this case, "A" is widely used, but it is still hard to say "Standard". If you do not have test on your ViewModel or you can test your ViewModel avoid touching dialogs, such as using Extract-Override, you can definitely do not follow the instruction.