How difficult is it to port Flex and Silverlight applications to HTML5? That is the question we hear every day at ComponentOne. Instead of speculating about it, we decided to sit down and try it. Today we will discuss the process and tools we used when doing so. The approach we took was to use the MVVM pattern (from Silverlight) when developing the HTML5/JavaScript version. By choosing this method we were able to port our data access and UI layers quite easily. Our developers were able to minimize the cost of learning new paradigms in this migration by reusing most of their knowledge. What we ended up with was nearly identical applications in Silverlight and HTML5. Come learn how you can smoothly transition to HTML5!

1. A Smooth Transition to HTML5
Using MVVM Development Patterns

2. @b4nn0n
chrisb@wijmo.com
CHRIS BANNON

3. WIJMO – UI FOR THE WEB
• 40+ Widgets
• Built on jQuery UI
• Powered by HTML5
• Themed with Themeroller
• Works Everywhere
• Supports MVVM

4. REAL WORLD EXAMPLES

5. WHY USE HTML5?
“Virtually every computing
device supports HTML and
JavaScript”

6. BENEFITS OF USING HTML5
• Mobile
• Performance
• Shared code in multiple platforms
– Mobile Web
– Native Mobile (PhoneGap)
– Desktop Web
– Native Desktop (Win8)

7. PRINCIPLES WHEN MIGRATING TO HTML5
• Port your programming knowledge
• Port your patterns & practices
• Port your code conventions
• Port your business logic, not your code

8. HOW TO MIGRATE TO HTML5

9. HOW CAN YOU PORT TO HTML5?
Use a familiar development pattern: MVVM
– Widely used by Flex/Silverlight developers
– Use Knockout for MVVM in JavaScript
– Use UI controls with MVVM support for
quicker development

10. WHAT IS MVVM?
• Model
– Data for an application
– Example: Web service
• ViewModel
– Pure code representation of UI Model
– Example: JavaScript Class or Object
• View
– Visible and Interactive UI
– Example: HTML, CSS & JavaScript UI

11. EXAMPLE VIEWMODEL USAGE
var myViewModel = {
personName: ko.observable('Bob'),
personAge: ko.observable(123)
};
ko.applyBindings(myViewModel);
<span data-bind="text: personName"></span>

12. PORTING THE MODEL
Use the same Model/Datasource
– Most JavaScript apps can use the same
services

13. PORTING THE VIEW-MODEL
Port the ViewModel
– Create JavaScript Objects/Classes that match
their equivalents in C#
– Hook up observability using Knockout
– Remember to focus on porting business logic,
not code

14. PORTING THE VIEW
Port the View
– Create HTML markup that represents your UI
(similar to what you have in MXML/XAML)
– Add data-bind attributes to bind markup to the
View-Model
– Use data-bind attributes to turn markup into UI
Controls (like Wijmo widgets)

15. THE BENEFITS OF USING MVVM

16. SHORTER DEVELOPMENT CYCLES
• MVVM separates development clearly
between Data, Code and UI
• Each layer can be developed in parallel
and individually
• Minimizes turnaround time

17. IMPROVED RELIABILITY / EASIER MAINTENANCE
• ViewModels are testable
• ViewModels easily integrate with Unit
Tests
• Unit Tests become assets to the project
during the lifecycle of the application
• Maintenance made easier with automated
tests

18. MORE PREDICTABLE DEVELOPMENT CYCLES
• Our steps in development:
– Design the View (general appearance and
behavior)
– Design the ViewModel to support the View
– Implement the ViewModel
– Implement the View
• This allows us to more easily estimate
time/cost for each step

19. IMPROVED QUALITY
• Less overlap between developers and
designers
• Each can focus on their specialty and
deliver higher quality
• Both can work simultaneously

20. FLEXIBILITY
• Loose coupling between Views and
ViewModels
• Multiple Views can use a single
ViewModel
• Easily make Mobile, Desktop or other
custom Views against a single ViewModel

21. STANDARDIZATION
• Use the same binding mechanisms in multiple applications
• Once initially developed these assets can be reused in new
applications
– Markup
– Styles
– UI Controls
– Common Input Forms
– Libraries (Globalization, shared functions, etc)

22. CHALLENGES WHEN PORTING TO HTML5

23. DEVELOPMENT TOOLS
JavaScript development tools are not as
mature as Flex/Silverlight’s
– Compile-time error detection
– Code re-factoring
– IntelliSense (Code Auto-complete /
Suggestions)

24. UI CONTROLS
Flex/Silverlight have a wider variety of UI
controls available to developers
– Only basic elements in HTML to use
– Usually need to use a library of UI Controls
– More difficult to create controls in HTML than
in Flex/Silverlight

25. DATA ACCESS
Flex/Silverlight provide a rich and mature set of
business data tools
– No concept of data queries
– Rich data features are not native to collections
(arrays)
– Must use ajax to call services and consume data

26. QUESTIONS?

27. RESOURCES
• Wijmo MVVM Support
http://wijmo.com/widgets/mvvm-support/
• Download Wijmo
http://wijmo.com/downloads/
• Knockout
http://knockoutjs.com/
• Contact Me
@b4nn0n
chrisb@wijmo.com

28. THANKS FOR JOINING!