The Model-View-ViewModel pattern was introduced for Windows Presentation Foundation applications (WPF) and later exploded in popularity with the introduction of various frameworks to support development on additional platforms including Silverlight and Windows Phone. The release of KnockoutJS the pattern has extended MVVM to the web and exposed it to the JavaScript stack, while the new Windows 8 Metro platform embraces the same XAML and C#-based technologies that WPF and Silverlight pioneered. In this talk, Jeremy Likness takes a deep dive into the history of the pattern, describes its benefits, and discusses how it relates to modern application development. Is it a bad fit for web applications? Does it belong in the Metro space? Learn the benefits and trade-offs to help decide if this pattern makes sense in your projects moving forward.

1. MVVM for Modern App Dev
Jeremy Likness
Senior Consultant, Project Manager
Twitter: @JeremyLikness
Blog: http://csharperimage.jeremylikness.com/
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5. Agenda
• What is MVVM?
• Why use MVVM?
• 10 Reasons to Use MVVM
• MVVM Frameworks
• What is the Cost?
• Demo: Portable Library
• Demo: Web Applications
• Questions
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6. What is MVVM?
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7. What is MVVM?
• Do you ever have to start work on an application before the
design team is ready?
• Do you make updates in parallel with the design team?
• Do you unit test your solutions?
• Do you reuse code and components both within and across
projects?
• Do you ever have to change the user interface, and wouldn’t
it be nice to do it without having to hit your code as well?
• MVVM solves these types of problems!
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8. What is MVVM? To any given Model there is
attached one or interface between
An Editor is an more Views, each a
user and one or more views. It
View being capable of
Something that is of interest to the
provides the user with a
showing one or more pictorial
user. suitable be concrete, like a for
It could command system,
representations of the Model on the
• Thing-Model-View-Editor exampleor an on
house in the form of menus that
integrated
A Model could activehardcopy. A
screen and
is an be abstract, like a
representation
circuit. Itmay change dynamically
• 12 May 1979 – Trygve Reenskaug View is also able to perform such
new idea or to the in the form of It
of an abstraction
opinions about a
operations in a computingcontext.
accordingupon the Model that is
data
current
paper. It could be a whole, the
provides the Views with
reasonabely associated
system.
like a computer, or a part, like and
necessarythat View. a
Thing with coordination
circuit element.
command messages.
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9. What is MVVM? The Model
• Domain object
• Application solution
• Data/Information and/or Behavior
• Possible persistence information (id, GUID, etc.)
• Separate from “how it got there”
• Let’s be specific:
• C#
• VB
• JavaScript
• Etc.
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10. What is MVVM? The View
• What the user “sees” / experiences
• User-friendly format for presentation
• Multiple inputs (gestures)
• Behaviors
• Events
• Data-bindings
• Let’s be specific:
• XAML
• HTML5
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11. What is MVVM? The View Model
• The “controller” – holds state
• Doesn’t know about the view
• Exposes methods and commands
• Coordinates with services
• “Owns” models, and knows how to retrieve/update them
• Might be used in multiple views
• Can communicate with other view models
• Let’s be specific:
• C#
• JavaScript, etc.
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12. What is MVVM
What a
Presentation Layer View!
The Interface
Don’t deal with
all of this
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13. What is MVVM? The View Model
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14. 10 Reasons to Use MVVM
1. Separation of concerns/de-coupling.
2. Designer/developer workflow.
3. Unit testing.
4. Data-binding.
5. Code reuse.
6. Modularity.
7. Refactoring containment.
8. Extensibility.
9. Tools support (Windows Phone 7, MVVM Light, etc.)
10.Pattern vocabulary.
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15. 10 Reasons to Use MVVM
1.Designer/developer
workflow.
2.Unit testing.
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16. MVVM Frameworks
1. PRISM (Guidance/Quickstart)
2. MVVM Light
3. Jounce
4. Caliburn / Caliburn.Micro
5. Cinch
6. nRoute
7. Catel
8. Knockout.JS
9. Kendo UI
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17. How Much Does it Cost?
•Learning Curve (Developers)
•Bigger down payment (architecture,
infrastructure)
- Low interest rates and minimum monthly
payments!
•Visibility (de-coupling can backfire)
•Unnecessary complexity
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18. demo
MVVM
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19. Questions?
Jeremy Likness
Senior Consultant, Project Manager
Twitter: @JeremyLikness
Blog: http://csharperimage.jeremylikness.com/
consulting training debugging wintellect.com