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TRANSCRIPT
Silverlight n-tier Architecture
Thomas Juul, Senior Consultant, TENTEO
Show of Hands
How many of you do not write code on a daily basis?
Silverlight n-tier Architecture
Focus is Silverlight, but this architecture can also be applied to WPF, WinForms and to some extent ASP.NET
“If you get any group of architects into a room
and ask them to describe their ideal architecture,
each one will come up with a different answer”
Silverlight 2-tier Architecture
UI
Domain Objects
Repository
Silverlight Client Application Server
Services
Domain Objects
Repository
Database
Silverlight 3-tier Architecture
UI
Domain Objects
Repository
Silverlight Client
Services
Domain Objects
Repository
Application Server
Database
Database Server
Silverlight 4-tier Architecture
UI
Domain Objects
Repository
Silverlight Client
Services
Domain Objects
Repository
DMZ Application Server
Services
Domain Objects
Repository
Application Server
Database
Database Server
Walkthrough
• Write business logic once, reuse on server and client
• Loosely coupled UI
• Loosely coupled UI Communication
• Async network Communication
• Mock the Repository
• Testability
Where to place the business logic?
Two approaches
”True” Object-Oriented Paradigm
BehaviorData
Access
Code
State
”Semi” Object-Oriented Paradigm
Behavior State
Data
Access
Code
Model-View-ViewModel aka Presentation Model
2-way through Data Binding
View
ViewModel
Model
Complexity
N-tier design will increase complexity for small applications, but decrease complexity for large applications
Talk is cheap. Show me the code!!
WCF Services
Server Repository
Client Repository
UI Shell
UI module X
UI module Y
Unity
Model
Unity
Not Quite UML..
Best Practice / Our Practice...
• Do share the Business Logic (model)
• Do block the UI (area) when making service calls
• Do use SSL to secure data on the wire
• Do protect the WCF services with authentication
• Avoid the generated proxy
• Consider using prism for loosely coupled UI & Communication
• Consider using DI to manage dependencies / mock
• Consider to bundle the service calls
• Consider using compression
• Do use a framework to encapsulate logic like this
Frameworks functionality
Functionality that almost any Line-Of-Business application needs (silverlight or not)
- State tracking- Validations rules- Undo support- Full data binding support- Authorization - Authentication- Job scheduling- and more…
Frameworks
• CSLA.NET- http://www.lhotka.net/cslanet/
• RIA Services- http://code.msdn.microsoft.com/RiaServices
• PRISM-http://compositewpf.codeplex.com/
• Build-It-Yourself approach…
