This document provides an overview of the Model-View-ViewModel (MVVM) pattern for building WPF and Silverlight applications. It discusses UI patterns, why they exist, and the MVVM pattern specifically. It then covers key WPF concepts like data binding, commanding, and notifying property changes that are foundational to MVVM. Available frameworks that can help with MVVM are presented, followed by a demo of writing a simple ViewModel and dashboard using MVVM principles. Resources for further reading on MVVM and WPF/Silverlight development are provided at the end.

2. Getting Started
with MVVM in
(WPF / Silverlight)
NISHANTH ANIL
TECHNICAL EVANGELIST
@nishanil | nanil@infragistics.com | nnish.com
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3. Agenda
– Patterns
– What’s MVVM?
– Foundation (WPF concepts)
– Available Frameworks
– Your First ViewModel (demo)
– Simple Dashboard (demo)
@nishanil

4. Patterns – are guidelines not rules!
• UI patterns
– Model – View – Controller
– Model – View – Presenter
– Presentation Model
– Model – View – ViewModel
• Why do they exist?
– Separation of concerns
– Testability
– Maintainability
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5. MVVM
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6. Foundation – WPF Concepts
• INotifyPropertyChanged/INotifyCollectionChanged
• DataContext
• DataBinding
• Commanding
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7. Foundation – WPF Concepts
• INotifyPropertyChanged
– Not a WPF only concept (part of an implementation of GOF Observer pattern)
• Observer Pattern in brief: When one object changes state, all its dependents are notified and updated automatically.
– Implement INotifyPropertyChanged in your ViewModels
– And Notify when property changes
• INotifyCollectionChanged
– Similar to INotifyProperyChanged, but it applies to collections of objects
– Use ObservableCollection<T> instead of manually implementing
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8. Foundation – WPF Concepts
• DataBinding
– A View binds to properties on a ViewModel
• DataContext
– Set ViewModel to the DataContext of the View
– This property is meant to be set to the data object it visualizes.
@nishanil

9. Foundation – WPF Concepts
• Commanding
– Is an input mechanism
– Without command MVVM will be less powerful
– Commands in WPF are implemented using ICommand interface
ICommand Implementation
ViewModel
Binding the command in the View
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10. Available Frameworks
Source: Wikipedia, As on 31st OCT 2012 @nishanil

11. Some helper files
• MVVM Foundation
– http://mvvmfoundation.codeplex.com/
– ObservableObject Class
– RelayCommand
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12. Demo
• Writing your first ViewModel
• A simple Sales dashboard
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13. Silverlight: MVVM + RIA
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14. Resources
• Introduction to Model/View/ViewModel pattern for building
WPF apps (John Gossman)
– http://blogs.msdn.com/b/johngossman/archive/2005/10/08/478683.a
spx
• WPF Apps With The Model-View-ViewModel Design Pattern
(Josh Smith)
– http://msdn.microsoft.com/en-us/magazine/dd419663.aspx
• Infragistics Community –
http://www.infragistics.com/community/blogs/
• Infragistics WPF Products -
http://www.infragistics.com/products/wpf/
• Infragistics Silverlight Products -
http://www.infragistics.com/products/silverlight/
@nishanil

15. Q&A
NISHANTH ANIL
TECHNICAL EVANGELIST
@nishanil | nanil@infragistics.com | nnish.com
facebook.com/InfragisticsIndia