How to update a list in parent view with data from child view/window ?

Question

I have a view named AccountListView that displays some buttons and a list of accounts.Its viewmodel is called AccountListViewModel and has a collection : ObservableCollection<AccountViewModel>. What I'd like to acomplish: whenever I press the Add/Edit
Button from the AccountListView to open a new window/usercontrol, i.e. AccountView and bind it to an instance of AccountViewModel that will have some fields to fill in and a Submit and Cancel buttons. How can I update the ObservableCollection<AccountViewModel>
from  inside the child view, so when I click on the Submit button from AccountViewModel it will return an AccountViewModel object with the data I filled in and add it to the observablecollection. Would notifications from prism be the right way ? Should
I include code from the AccountListViewModel and AccountViewModel ?

Answer 1

The way to communicate between view models in Prism is to use the EventAggregator. You raise an event from view model A and subscribe and handle this event in view model B. I have written a blog post about it which should be helpful here:
http://blog.magnusmontin.net/2014/02/28/using-the-event-aggregator-pattern-to-communicate-between-view-models/.
In your case you could define an event that carries an AccountViewModel object and pass this one from view model A to view model B:
public class AccountViewModelEvent : CompositePresentationEvent<AccountViewModel>
Please refer to the blog post for more information and a complete code example.
Hope that helps.
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