Confirmation when closing window with 'X' button with MVVM light

Question

I am using WPF and MVVM Light framework (I am new in using them).

I want to do the following:

1. When the user click on the \'X\' close button, I want to

Answer 1

The Closing event arguments have a Cancel property that you need to set to true if the user cancels the close. Therefore, your Cleanup() method should return bool and you should assign it to the Cancel property.