A Smooth Transition to HTML5 Using MVVM

How difficult is it to port 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. We take advantage of tools like KnockoutJS and Wijmo to make the process even easier. 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!

Transcript

1. A Smooth Transition to HTML5 Using MVVM Development Patterns
2. About: me Chris Bannon @b4nn0n chrisb@wijmo.com
3. Wijmo • 40+ Widgets • Built on jQuery UI • Powered by HTML5 • Themed with Themeroller • Supports MVVM
4. About: session • Philosophical (warning: lot’s of talking) • Share our approach on porting to HTML5 – General guidelines – Tools – Pitfalls • Show some code!
5. Real World Examples
6. Why Use HTML5? “Virtually every computing device supports HTML and JavaScript”
7. Benefits of Using HTML5 • Mobile • Performance • Shared code in multiple platforms – Mobile Web – Native Mobile (PhoneGap) – Desktop Web – Native Desktop (Win8)
8. Principles When Migrating to HTML5 • Port your programming knowledge • Port your patterns & practices • Port your code conventions • Port your business logic, not your code
9. How to Migrate to HTML5
10. How Can You Port to HTML5? Use a familiar development pattern: MVVM – Widely used by Silverlight developers – Use Knockout for MVVM in JavaScript – Use UI controls with MVVM support for quicker development
11. 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
12. Example ViewModel Usage var myViewModel = { personName: ko.observable('Bob'), personAge: ko.observable(123) }; ko.applyBindings(myViewModel); <span data-bind="text: personName"></span>
13. MVVM Examples Using Knockout for MVVM in JavaScript
14. Porting the Model Use the same Model/Datasource – Most JavaScript apps can use the same services
15. Porting the ViewModel 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
16. Porting the View Port the View – Create HTML markup that represents your UI (similar to what you have in XAML) – Add data-bind attributes to bind markup to the View-Model – Use data-bind attributes to turn markup into UI Controls (like jQuery UI widgets)
17. The Benefits of Using MVVM
18. Shorter Development Cycles • MVVM separates development clearly between Data, Code and UI • Each layer can be developed in parallel and individually • Minimizes turnaround time
19. 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
20. 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
21. Improved Quality • Less overlap between developers and designers • Each can focus on their specialty and deliver higher quality • Both can work simultaneously
22. 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
23. 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)
24. Challenges When Porting to HTML5
25. Development Tools JavaScript development tools are not as mature as Silverlight’s – Compile-time error detection – Code re-factoring – IntelliSense (Code Auto-complete / Suggestions)
26. UI Controls Silverlight has 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 Silverlight
27. Data Access Silverlight provides 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
28. Questions?
29. 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
30. Thanks for Joining!