Closing a window in MVVM pattern

But, imagine the following scenario: you have two buttons on your screen, one to save changes and close and another to cancel and close. But how do you close the window if your view model does not know what is the window and does not know how to handle UI logic?

To demonstrate it I will use MEF to keep a single instance of my EventAggregator across the system. For that I will annotate my class with the ExportAttribute (using System.ComponentModel.Composition;).

On my View I can get a instance of it. I will also implement IListen interface to be able to handle messages sent by others:

The CloseWindowMessage class:

I can then finally publish a message from my ViewModel notifying the view that it should close.

When the view receives the message it will call Handle which will close the window using the View’s logic for it. This way you have a view model decoupled from the view.

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