A Smooth Transition to HTML5 Using MVVM
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A Smooth Transition to HTML5 Using MVVM Development Patterns
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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 of A Smooth Transition to HTML5 Using MVVM
A Smooth Transition to HTML5
Using MVVM Development Patterns
Wijmo
• 40+ Widgets
• Built on jQuery UI
• Powered by HTML5
• Themed with Themeroller
• Supports MVVM
About: session
• Philosophical (warning: lot’s of
talking)
• Share our approach on porting to
HTML5
– General guidelines
– Tools
– Pitfalls
• Show some code!
Real World Examples
Why Use HTML5?
“Virtually every computing device supports HTML and JavaScript”
Benefits of Using HTML5
• Mobile
• Performance
• Shared code in multiple platforms
– Mobile Web
– Native Mobile (PhoneGap)
– Desktop Web
– Native Desktop (Win8)
Principles When Migrating to HTML5
• Port your programming knowledge
• Port your patterns & practices
• Port your code conventions
• Port your business logic, not your
code
How to Migrate to HTML5
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
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
Example ViewModel Usagevar myViewModel = { personName: ko.observable('Bob'), personAge: ko.observable(123)};ko.applyBindings(myViewModel);
<span data-bind="text: personName"></span>
MVVM Examples
Using Knockout for MVVM in JavaScript
Porting the Model
Use the same Model/Datasource
–Most JavaScript apps can use the same
services
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
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)
The Benefits of Using MVVM
Shorter Development Cycles• MVVM separates development clearly
between Data, Code and UI
• Each layer can be developed in
parallel and individually
• Minimizes turnaround time
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
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
Improved Quality
• Less overlap between developers
and designers
• Each can focus on their specialty and
deliver higher quality
• Both can work simultaneously
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
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)
Challenges When Porting to HTML5
Development Tools
JavaScript development tools are not
as mature as Silverlight’s
– Compile-time error detection
– Code re-factoring
– IntelliSense (Code Auto-complete /
Suggestions)
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
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
Questions?
Resources
• Wijmo MVVM Support
http://wijmo.com/widgets/mvvm-support/
• Download Wijmo
http://wijmo.com/downloads/
• Knockout
http://knockoutjs.com/
• Contact Me
@b4nn0n
