WPF + Caliburn Micro: how to catch Window Close event?

Question

I am new in Caliburn Micro and learn it from this helloworld example. In the example there are only 2 views (.xaml) of type Application and UserControl, and 1 view model.

I avoid to use code behind. Therefore I have only view and view model. I want to know how to catch the window close event of my helloworld application so I can handle it in view model. My target: when user is going to close the app by pressing close [x] button on top-right corner the app gives feedback to the user.
I have read about IViewAware and IScreen, but I find no specific example related to my question.

A simple sample code for view and view model are highly appreciated. Thanks in advance.

PS. I use VS2013, C#.

Answer 1

What you can do is in your View you can attach Caliburn Micro by using

cal:Message.Attach="[Event Closing] = [Action OnClose($eventArgs)]"

So it will look like

<Window cal:Message.Attach="[Event Closing] = [Action OnClose($eventArgs)]">

And on your ViewModel you can just define a public method that says OnClose with CancelEventArgs as the parameter and you can handle it from there.

Answer 2

If your ViewModel inherits Screen, Caliburn Micro has some methods that you can override like

protected override void OnDeactivate(bool close); 

this is called when a screen is closed or deactivated or

public override void CanClose(Action<bool> callback)

you can check CanClose usage here