Silverlight 2 for Developers - TechEd New Zealand 2008

Silverlight 2 for Developers Jonas Follesø Senior Consultant Capgemini Session Code: WEB304

Agenda
Blend 2.5
CRUD
Designers
Patterns
Testing
Q&A

Dive Log App

Outside data Public Internet mashup APIs Existing Intranet services New services you build RSS/Atom Feeds Images Sounds Videos

A bit of history: Silverlight 1 JavaScript HTML ? AJAX (XmlHttpRequest) 1.0 <XAML/> Public Internet mashup APIs Existing Intranet services New services you build RSS/Atom Feeds Images Sounds Videos

Today: Silverlight 2 2 Managed Code (C#/VB) HTML Public Int e rnet mashup APIs Existing Intr a net services New services you build RSS/Atom Feeds Images Sounds Videos

Services that describe themselves Computer-Readable Metadata (e.g. WSDL) Automatic Proxy Generation WCF SOAP services in the enterprise Services for your Silverlight project ADO.NET Data Services SOAP services on the Internet

Securing Silverlight Services Silverlight will use auth. info in the browser HTML E.g.: ASP.NET Login User: Password : Credentials Auth info (e.g. cookie) Service calls + Auth info Silverlight code does not normally deal with credentials… DiveLog.com …/Login.aspx ../MyApp.aspx ../MyService.svc

HTTP Requests in Silverlight HttpWebRequest High-level components and User Code Browser Plugin APIs Web Browser - Cookies - Authenticated sessions - Caching - Proxy server to use Windows/Mac Networking Layer Restrictions Restrictions

Blend – The dark is not that scary…

Dive Log UI and Data

Everything in code behind …is probably not a good idea

A team of sad coders and designers

Different people reading about MVC in different places take different ideas from it and describe these as “MVC”. Martin Fowler, GUI Architectures Essay

Separated Presentation Patterns

Data & Domain Logic (Model) UI (View) Interaction (Controller/Presenter)

Represent the state and behavior of the presentation independently of the GUI controls used in the interface. Martin Fowler, Presentation Model Essay

Makes your app easier to design …makes the designers like you

Everything in code-behind Data Model View XAML Code-Behind Event Handlers

Presentation Model Change notification Data-binding and commands Data Model View XAML Code-Behind Presentation Model State + Operations

Dive Log Presentation Model Change notification Data-binding and commands Dive Log Service Dive Log XAML Code-Behind Dive Log View Model State + Operations

Data Binding
Implement INotifyPropertyChanged and use ObservableCollection<T> for collections
View < ListBox ItemsSource ="{Binding Path=Dives}" SelectedItem ="{Binding Path=SelectedDive, Mode=TwoWay}" /> Presentation Model State + Operations

Data Binding
Implement INotifyPropertyChanged and use ObservableCollection<T> for collections
View XAML Code-Behind Presentation Model public class PageViewModel : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public ObservableCollection < Dive > Dives { ... } public Dive SelectedDive { ... } }

IValueConverter
Converts data bound values
E.g. Bind temperature to color
public object Convert( object , value, Type targetType, object parameter, CultureInfo culture) { int temp = System. Convert .ToInt32(value); Color color = Colors .Black; if (temp < 5) color = Colors .Blue; else if (temp < 20) color = Colors .Yellow; else color = Colors .Red; return new SolidColorBrush (color); } View < UserControl.Resources > < demo:ColorConverter x:Key ="colorConverter" /> </ UserControl.Resources > < TextBox Text ="{Binding Temperature, Mode=TwoWay}" Background ="{Binding Temperature, Converter={StaticResource colorConverter}}"/>

Building a Presentation Model

User Interaction
But what about Word?
View private void btnSave_Clicked( object sender, ExecutedEventArgs e) { (( PageViewModel )DataContext).Save(); }

Objects are used to represent actions. A command object encapsulates an action and its parameters. This allows a decoupling of the invoker of the command and the handlers of the command.

Commands in Silverlight View < Button Content ="Save Dives" input:CommandService.Command ="SaveDives" /> Presentation Model public PageViewModel() { Commands .SaveDives.Executed += new EventHandler < ExecutedEventArgs >(SaveDives); } private void SaveDives( object sender, ExecutedEventArgs e) { // code to save dives.. }

The strategy pattern is a software design pattern, whereby algorithms can be selected at runtime . Presentation Model public PageViewModel() { if ( HtmlPage .IsEnabled) { client = new DiveLogServiceClient (); } else { client = new ServiceStub (); } }

Dealing with dependencies
The Presentation Model is coupled with both the stub service and the real service.
Makes code less flexible for change
Makes code harder to test
Object should not be responsible for creating their own dependencies – Inversion of Control

Dependency Injection (DI)
One form of Inversion of Control (IoC)
Create dependencies outside the object and, inject them into it
But who creates the dependency?
Presentation Model public PageViewModel( IDiveLogServiceClient proxy) { this. proxy = proxy }

Dependency Injection by hand
Should the page be responsible for creating dependencies?
View public Page() { InitializeComponent(); if ( HtmlPage .IsEnabled) this .DataContext = new PageViewModel ( new DiveLogServiceClient ()); else this .DataContext = new PageViewModel ( new ServiceStub ()); }

IoC Containers Presentation Model [ Inject ] public PageViewModel( IDiveLogServiceClient proxy) { this. proxy = proxy } View public Page() { InitializeComponent(); IKernel iocContainer = new StandardKernel (); this .DataContext = iocContainer.Get< PageViewModel >(); }

IoC Containers
What about design time support in Blend?
Need to find a way to use IoC and set DataContext declaratively…
View < UserControl.DataContext > < dive:PageViewModel /> </ UserControl.DataContext >

Using DI on the ViewModel

Testing is important!

Testing Silverlight Code
The standard solutions do not apply
The Silverlight CLR is a subset
All networking is asynchronous
But it’s still familiar…
[TestClass], [TestMethod], [Asynchronous]

Asynchronous Tests
How do we “wait” before doing assertions?

Unit Testing in Silverlight

Resources
www.microsoft.com/teched
Tech·Talks Tech·Ed Bloggers
Live Simulcasts Virtual Labs
http://microsoft.com/technet
Evaluation licenses, pre-released products, and MORE!
http://microsoft.com/msdn
Developer’s Kit, Licenses, and MORE!

Related Content
Code and lots of good resources on http://jonas.follesoe.no
WEB311 Designing Compelling Silverlight User Experiences with Expression Studio 2
Wednesday, 3-9-2008 14:20 - 15:35, NZ Room 4, SkyCity
Hands-on Labs (session codes and titles)

Track Resources
WEB311 Designing Compelling Silverlight User Experiences with Expression Studio 2
Wednesday, 3-9-2008 14:20 - 15:35, NZ Room 4, SkyCity

Please complete an evaluation

© 2008 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

Photo Copyright Notices
All diving photos taken by Hege Røkenes and licensed under the creative commons license. http://flickr.com/photos/hegerokenes/
Photos of Martin Fowler taken by Dave Thomas and licensed under the creative commons license. http://flickr.com/photos/pragdave/

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Silverlight 2 for Developers - TechEd New Zealand 2008

by Jonas Follesø

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Silverlight 2 for Developers - TechEd New Zealand 2008 Presentation Transcript