CODEWITHSUNDEEP
.netwpfmvvmprismmvvm-light
JohnB
JohnB

Reputation: 4359

How do I notify a parent view of a child view event in an MVVM WPF application?

I have an MVVM based WPF desktop application. I'm utilizing MVVMLight and Prism to create user controls which contain views and sub-views.

I have button on a child view. (Let's say it's a close button)

What is the best way to propagate notification of the click event from the nested child view up to it's containing parent view?

Upvotes: 2

Views: 1443

Answers (1)

ivica.moke
ivica.moke

Reputation: 1064

With Prism EventAggregator.

1. Make event that you want to publish

public class CloseTabEvent : PubSubEvent<TPayload>
    {

    }

where TPayload is type you are passing(int, string, or even class object)

2. In your subView where your close button is, publish that event. In your close button Command (execute method) u publish that event.

private void OnCloseExecuted(object obj)
{
_eventAggregator.GetEvent<CloseTabEvent>().Publish(SomethingThatYouPublis..ThisIsTPayload);
}

In your subView constructor pass IEventAggregator and make a private field.

private IEventAggregator _eventAggregator;
public SubViewModel(IEventAggregator eventAggregator)
{
_eventAggregator = eventAggregator;
}

3. In your mainViewModel you also pass IEventAggregator and subscribe inside constructor.

public MainViewModel((IEventAggregator eventAggregator)
{
    eventAggregator.GetEvent<CloseTabEvent>
   ().Subscribe(MethodForClosingThatSpecificTab);
}

And that's it.

IMPORTANT: When resolving IEventAggregator with some IoC(Unity, Autofac..) make it singleton, so it's one for whole app.

Upvotes: 1

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