Architecting Silverlight Applications with MVVM Shawn Wildermuth President AgiliTrain Session Code: WIA301

The Problem

The Problem (2) Tight Coupling Adds Complexity Simple Changes Cascade Difficult to Test Difficult to Develop Large Applications

Separation of Concerns Loose Coupling Layers are Individually Responsible Established Patterns Lessens the Need to Reinvent Architecture

Patterns Model-View-Controller Model-View-Presenter Model-View-ViewModel

Patterns (2) XAML is Declarative Allows for Code-less Views Older Patterns Don’t Fit

Model-View-ViewModel

Model-View-ViewModel (2) Silverlight XAML View C#/VB ViewModel Model Internet Server C#/VB Services

Building the MVVM Planning on MVVM Build in Tiers Plan for Testing

Building the MVVM (2) The Model Expose Data as Collections Expose Methods for Different Data Shaping More than one ViewModel May Use a single Model Build Interface Providing Data Allows Mocking of the Database if necessary Eliminate Tight Coupling of Services with Model

demo The Model

Building the MVVM (4) The ViewModel Expose API that the View Needs Use the Model to Provide the Data

demo The ViewModel

Building the MVVM (6) The View Declarative UI Use as Much XAML as Possible Don’t Write Code to Rebind Data Perfect View is Code-less In Silverlight 3 Behaviors and Element Binding Help

demo The View

Evolving Pattern MVVM is Still Growing Some Frameworks Support it (e.g. Prism) Philosophy of Specifics is not settled View-Centric ViewModel-Centric Marriage/Mediator No Completely Right/Wrong Way to Implement It Patterns Only Good If They Help

Frameworks I Hand-Coded MVVM Frameworks Help Laurent Bugnion’s Light MVVM http://www.galasoft.ch/mvvm/getstarted/ Nikhilk Kothari’s FX Framework http://projects.nikhilk.net/SilverlightFX Michael Sync’s Silverlight MVVM Toolkit http://silverlightmvvm.codeplex.com/

question & answer

Resources www.microsoft.com/teched www.microsoft.com/learning Sessions On-Demand & Community www.microsoft.com/learning Microsoft Certification & Training Resources http://microsoft.com/technet Resources for IT Professionals http://microsoft.com/msdn Resources for Developers

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