DEV322 Visual Studio 2005 C

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ASP.NET MVC
Matthew D. Groves
Student Life IT Web Developer
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Brief history of MVC

• First used in Smalltalk
• Xerox PARC
• 1979
• Trygve Reenskaug
• Struts (2000), Ruby on Rails (2005)
• ASP.NET MVC
• ASP.NET launched as CTP on December 10, 2007
• Preview 2 launched March 5, 2008
• Preview 3 launched May 1, 2008

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Scope of this presentation

• Introduction to ASP.NET MVC and syntax
• Introduction to .NET syntax useful for MVC
• Quick introduction to TDD
• Not exhaustive
• Not a detailed tutorial

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Scope of this presentation

• Visual Studio 2008
• ASP.NET 3.5
• C
• MVC is not part of the .NET framework yet

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MVC diagram
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M is for Model

• Components of the application responsible for
  maintaining state
• State is persisted via a database
• For instance, a Product object may represent a
  row in a Product table in a SQL DB

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V is for View

• Display / UI
• List.aspx list of all products
• Detail.aspx details of a product
• New.aspx add a new product

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C is for Controller

• Handles user interaction / form submissions
• Manipulates the model
• Chooses a view

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Why ASP.NET MVC?

• True, clean separation
• Components designed to be replaced / customized
• Probably the big difference is that Rails will
  make it difficult for you if you don't think in
  MVC, while ASP.NET couldn't care less. This is
  something we will see a lot with Ruby on Rails
  the Rails architecture will intentionally make
  things difficult if you do not follow its
  conventions. Tom Rossi (themolehill.com)
• Efficient, easy development
• Maintainability
• Test driven development (TDD)

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Test Driven Development

• Red/green testing
• Write automated test script for some specific
  functionality
• Run the test, watch it fail
• Write code to pass the test
• Run the test, watch it succeed
• Repeat

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MVC diagram
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URL routing

• URLs have a logical mapping
• Friendly URLs
• Distinct from MVC, but integral
• /Products/Categories
• Products controller
• Categories action gt View of all categories
• /Products/Detail/ProductID
• Products controller
• Detail action gt Details view of ProductID
• http//website/Products/Detail/34

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Example application

• Visual Studio 2008
• File-gtNew Project -gt ASP.NET MVC Web Application
• Two projects
• Application
• Test project

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MVC diagram
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Products Controller
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Products Controller Syntax
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MVC diagram
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Model

• LINQ to SQL is an ORM
• LINQ Language Integrated Query
• ORM Object Relational Mapping

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NorthwindDataContext
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NorthwindDataContext
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Syntax Break

• Partial class
• Class is split into multiple files
• ListltTgt
• Generic list of objects of type T
• ListltCategorygt is a list of Category objects
• Why? Functionality and helper methods

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Syntax Break

• Lambda expression
• Concise, anonymous expressions
• Code blocks written inline
• Useful for LINQ expressions
• foreach functionality

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MVC diagram
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Back to the controller

• DataContext with some helper functions
• Retrieve data needed for Categories view
• Render the categories view with the
  ListltCategorygt as ViewData

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ProductsController
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MVC diagram
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Recall the controller.

• The controller is querying via the models
  helper function, GetCategories()
• Passing off the data that needs to be rendered to
  the Categories view.

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Views

• Folder structure
• /Shared
• Master pages
• User controls
• Any view used for multiple controllers
• /Products
• Views for Products specifically
• Standard CRUD goes here

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Categories view

• Categories.aspx.cs

Categories.aspx
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Syntax Break

• Views inherit from ViewPage class by default
• ViewData is a bag of data
• Strongly typed view
• View inherits from ViewPageltTgt
• Where T is the type of ViewData that is passed
• Full intellisense

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More on views

• Can be coded inline, like standard ASP classic /
  PHP
• Can be coded via code-behind pages with standard
  ASP.NET controls
• Forms are just submitted to controllers for
  processing

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Views Links and URLs

• Hardcoded links
• Html.ActionLink to avoid hardcoding URLs
• Html.Form lambdas allow for strongly typed
  links/actions

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Views Form field names

• Use a naming convention on form fields
• nameProduct.ProductName
• nameProduct.ProductPrice
• Doing so allows for easy data binding in the
  controller
• Flexible, optional

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Views Validation

• Done in the controller
• Typical example
• New() controller directs to blank form view
• Blank form view submits to Create() controller
• Create() controller performs validation, creates
  error message
• If valid, data is updated/inserted/deleted,
  redirect to list
• If invalid, redirect back to the New() controller
  with a persisting context and error message

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MVC diagram
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Unit testing

• ASP.NET MVC designed specifically to enable easy
  unit testing
• Back to the test project when this application
  was first created

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Test project
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Syntax Break

• TestClass
• class full of test methods
• TestMethod
• Indicates methods that are run when running all
  tests
• Should have descriptive names
• Controller object instantiated
• TestViewEngine provides a simulated browser
  environment (server variables, form, session,
  etc)
• Controller action is performed
• Assert(s) are used to verify action success

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More information

• ScottGu (Scott Guthrie)
• http//weblogs.asp.net/scottgu
• Youve been Haacked (Phil Haack)
• http//haacked.com/
• WekeRoad (Rob Conery)
• http//blog.wekeroad.com/
• Microsoft
• http//asp.net/mvc

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ASP.NET MVC
Matthew D. Groves
Student Life IT Web Developer