Comments on: Model-View-ViewModel in Silverlight and Flex

By: Alain

Alain — Wed, 30 Jun 2010 14:05:50 +0000

Thanx for the comments, and I agree with you that you better use dependency injection and interfaces to connect your View and the ViewModel. In Silverlight I usually create a ViewModelLocator, that is responsible for creating the ViewModels. These can be created with or without dependency injection. And to send back messages from the View to the ViewModel, this can be done through the Command pattern.

However, this was a very simple demo. And I didn’t want to overarchitect the demo. It served as a example to see if some practices from Silverlight could work also in Flex.

Alain

By: Martin

Martin — Tue, 29 Jun 2010 14:57:27 +0000

The purpose of the Presentation Model pattern is to capture state and behaviour of Presentation independently of the View.

What this essentially means is that the View should be as oblivious to your Model, as the Model is oblivious to the View. It provides a surface of abstraction from the point of a View and a Model, and one could think of it as a kind of interface on steroids.

As an example, if we write a hotel booking application, the abstract interface (Presentation) – that is interactivity and perceivable state; user I/O – is defined separately. We may then develop several concrete projections (Views) that all use this interface, be it a CLI, desktop GUI or web application.

The Flex example provided in this article violates the fundamental idea of the Presentation Model pattern in that the View is hardwired to the Model.

On a side note, a canonical implementation of Presentation Model should decouple the the View from the ViewModel, and the ViewModel from the Model as well. This can be achieved by using interfaces and dependency injection, to name one approach.

Cheers!

By: Understanding the Model-View-ViewModel Pattern | Alain Hufkens

Understanding the Model-View-ViewModel Pattern | Alain Hufkens — Tue, 23 Mar 2010 21:08:57 +0000

[...] post is a follow-up on my previous post concerning the Model-View-ViewModel Pattern in Silverlight. Laurent Bugnion (@LBugnion) talks about [...]

By: Understanding the Model-View-ViewModel Pattern | Alain Hufkens

Understanding the Model-View-ViewModel Pattern | Alain Hufkens — Tue, 23 Mar 2010 21:08:57 +0000

[...] post is a follow-up on my previous post concerning the Model-View-ViewModel Pattern in Silverlight. Laurent Bugnion (@LBugnion) talks about [...]

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