The document summarizes the presentation model pattern and Model-View-ViewModel (MVVM) design pattern. It discusses how MVVM is an implementation of the presentation model pattern for WPF and Silverlight applications. It outlines key aspects of MVVM like separating the view and view model, using XAML for views, data binding between views and view models, commands, validation, messaging between components, and view model locators. The document provides examples of how to implement features like data binding, commands, and validation using MVVM.

1. Presentation Model
The First Contact

2. Agenda
 Quick Introduction
 Why should I care about it?
 View Model
 XAML
 Data Binding
 ViewModel Base
 Commands
 Validation
 Data Templates
 Resource Systems
 MVVM Framework
 How do I do…?

3. Quick Introduction: Presentation Patterns

4. UI Patterns Comparison
 Passive View
 Supervising Controller
 Presentation Model

5. Presentation Model
“Probably the most annoying part of the Presentation Model is the
synchronization between Presentation Model and view. It’s simple code
to write, but I always like to minimize this kind of boring repetitive
code.
Ideally some kind of framework could handle this, which I’m hopping
will happen some day with technologies like .NET’s data binding.”
Martin Fowler, 2004.

6. Model – View – ViewModel
 Technology specific implementation of the PM
 Separation of Markup and Code
 Behaviour of the Application
 Look and Feel
 Tool Support

7. “Once a developer becomes comfortable
with WPF and MVVM, it can be difficult
to differentiate the two. ”. Josh Smith, MVVM Guru

8. Why should I care about it?
 Order vs. Chaos
 Technology Choice
 Loose Coupling
 Testability (DEMO)
 Maintainable Code
 Blendability (DEMO)
 It is cool

9. <Disclaimer>
 No Solution is Perfect
 Different Approaches
 View-Centric
 ViewModel Centric
</Disclaimer>

10. View Model
 Separation of Concerns
 Enables code reuse
 State + Operations
 Provides a Bindable Surface
 Not Dependent on the View
 Typically One-To-One ViewModel to View
 One-To-Many is very common though

11. XAML
 Humble View
 Plays nicely with Data Binding
capabilities

12. Data Binding
 Binding Expression
 Binding Direction
 Binding to Elements
 Binding to Templates
 RelativeSource

13. DEM
O

14. Commands
 Delegate Command vs. Relay Command (DEMO)
 Uses WPF Behaviours capabilities
 Map Events to Commands (DEMO)

15. DEM
O

16. Validation
 Implemented on ViewModel, not in Model Class

17. DEM
O

18. Messaging
 Uses a light message bus to communicate between components
 Publish/Subscribe
 Frameworks (MVVM Light) (DEMO)

19. DEM
O
MVVM Light Toolkit

20. ViewModel Locator
 Repository of ViewModels
 Uses WPF DataTemplate Capabilities
 One View per ViewModel
 MVVM Light

21. DEM
O
MVVM Light Toolkit

22. Trade-Offs
 Agregate Model vs Proxy Property
 Start animation on the View through ViewModel
 How to close a window
 Clean and Shutdown
 Handle Navigation
 Add your own topic to be discussed…

23. And continues…
Not used only with WPF/Silverlight:
 ASP.NET MVC
 Knockout.js
 Java frameworks (RLY?)
To Far and Beyond… That’s it ;-)