Best Practice Observablecollection<Model> vs Observablecollection<ViewModel>

Question

Which one is the better solution to hold my data or does it depends on some conditions?

sample situation 1:
you need to display a list of data which can be modified in an new window after selection.

sample situation 2:
you need to display a list of data which can be modified in this list.

Answer 1

As you're using MVVM, you should be going with ObservableCollection<ViewModel>.

The Model should be separated from the View by means of the ViewModel.