Applying Domain Driven Design on
Asp.net MVC
Mohamed Meligy

Agenda
 ASP.NET MVC, The Steps
 Model, Controller, View
 Why ASP.NET MVC
 Domain, AKA, Model
 The Domain Model
 The Ubiquitous Language
 Building Blocks
 Entities / Value Objects
 Aggregates / Factories
 Repositories
 Services / Modules
 Putting it all together

Model
View Controller
ASP.NET MVC – Form few thousand feet …

ASP.NET Futures Themes
 Webforms
 AJAX
 MVC
 Dynamic Data
 Feature Sharing
 Webforms with AJAX
 Dynamic Data with MVC
…
 jQuery

M – V – C, The Steps …
Routing
Request
Forward
Step 0
Incoming request matched by Routing

M – V – C, The Steps …
Controller
Request
Step 1
Incoming request directed to Controller

M – V – C, The Steps …
Controller
Request Model
Step 2
Controller processes request and forms a data Model

M – V – C, The Steps …
Controller
Request
View
Step 3
Model is passed to View

M – V – C, The Steps …
Controller
Request
View
Step 4
View transforms Model into appropriate output format

M – V – C, The Steps …
Controller
Request
View Response
Step 5
Response is rendered

The ASP.NET MVC Building Blocks
Simply creating a new project

The model
 The class that needs to be presented, or processed
 Can be bound in controller
 Model Binders
 Can live anywhere in your solution

The Controller
 A set of action methods that share a common
Controller context
 … which is different from HTTP context 
 An action:
1. Receives the request parameters
2. Creates any required model (user, etc..)
3. Calls services or repositories to execute data or get
the models to be displayed
4. Selects the view and sends the model to it, with any
additional info (like page title, …)

The ASP.NET MVC Building Blocks
ROUND TWO !!

The View
 Just renderer
 No logic should go there
 Page lifecycle ?
 Yes and No!
 Code Behind exists but not recommended
 No View State, No Server Controls
 Really?
 HTML Helpers
 Takes the view data from the controller
 Can be typed or Dictionary of values
 Not Just Web forms code
 View Engines

View Engines
Web forms
• The default option
• Comes with VS
• Same experience:
• Syntax
• VS Support

View Engines
NHAML
• Based on Ruby On Rails HAML Engine
• http://code.google.com/p/nhaml
• http://andrewpeters.net/2007/12/19/introducing-nhaml-an-aspnet-mvc-view-engine
engine

The webforms view Engine
From ASP.NET MVC source code

Why Oh, WHY !!!
 Easier …
 Tight control over markup
 User/SEO friendly URLs
 Conventions and Guidance
 jQuery (Built-in)
 Tight control: Not just markup
 Everything is replaceable
 Interface based style
 Not full with sealed/internal stuff 
 Testability
 The guys who created it are just awesome 
 94% Code Coverage/1051 unit tests

The other side of the story
 It’s not as easy as you think!
 To go low level or not to go; this IS the question.
 IIS 6 Quirks
 Custom Controls

Where to go
 Official website http://asp.net/mvc
 Source Code http://codeplex.com/aspnet
 Blogs
 The ASP.NET MVC Team
 Scott Guthrie http://weblogs.asp.net/scottgu
 Rob Conrey http://blog.wekeroad.com
 MVC Store Front http://blog.wekeroad.com/mvc-storefront
 Phil Haack http://haacked.com
 Scott Hanselman http://hanselman.com
 Stephen Walthler http://weblogs.asp.net/stephenwalther
 http://www.chrisvandesteeg.nl
 http://www.singingeels.com

http://weblogs.asp.net/meligy