ASP.net MVC Owen Evans Developer, Xero

or

Welcome to the new (old) way MVC – Model-View-Controller About architectural separation Not a new pattern, first attributed to Trygve Reenskaug, working in smalltalk at Xerox Parc Convention over configuration Less to think about (no page object model) Easier to unit test

MVC – Model-View-Controller

About architectural separation

Not a new pattern, first attributed to Trygve Reenskaug, working in smalltalk at Xerox Parc

Convention over configuration

Less to think about (no page object model)

Easier to unit test

Lots of MVC Frameworks Some well known: Rails, Merb, Monorail, Grails, Spring MVC Framework, Dojo, Django, Silverstripe, Flex, Swing, Others not so Check Wikipedia for links to lots of frameworks

Some well known:

Rails, Merb, Monorail, Grails, Spring MVC Framework, Dojo, Django, Silverstripe, Flex, Swing,

Others not so

Check Wikipedia for links to lots of frameworks

The MVC pattern Controller View Model

MVC vs. Classic ASP.net ASP.net Classic ASP.net MVC

ASP.net Classic

ASP.net MVC

Model The computer model. The representation of the system within your application domain Business objects, services, data access etc The application core

The computer model. The representation of the system within your application domain

Business objects, services, data access etc

The application core

Controllers Direct all the action of a request Make calls to models to gather data Sends business object and information to a particular view. Makes decisions for security, UI, redirects etc. Provides the glue between the mental model and the computer model

Direct all the action of a request

Make calls to models to gather data

Sends business object and information to a particular view.

Makes decisions for security, UI, redirects etc.

Provides the glue between the mental model and the computer model

A Basic Controller public class HomeController : Controller { public ActionResult Index() { var message = someService.GetAMessage() return View(message); } } Interacts with the model and gets a message Puts the message to the default view Only one action/view for this controller

public class HomeController : Controller

{

public ActionResult Index()

{

var message = someService.GetAMessage()

return View(message);

}

}

Interacts with the model and gets a message

Puts the message to the default view

Only one action/view for this controller

View Responsible for displaying a given expectation of data. Will interact with model but shouldn’t make decisions over what entities to display, shouldn’t make CRUD actions etc. Purely about representing the mental model of the system. Not restricted to aspx, can also use Nhaml, Brail, XSLT to name but a few, just implement a ViewEngine if you want your own view syntax

Responsible for displaying a given expectation of data.

Will interact with model but shouldn’t make decisions over what entities to display, shouldn’t make CRUD actions etc.

Purely about representing the mental model of the system.

Not restricted to aspx, can also use Nhaml, Brail, XSLT to name but a few, just implement a ViewEngine if you want your own view syntax

A Basic View <%@ Page Language=&quot;C#&quot; MasterPageFile=&quot;~/Views/Shared/Site.Master&quot; AutoEventWireup=&quot;true&quot; CodeBehind=&quot;Index.aspx.cs&quot; Inherits=&quot;Basic_MVC_Project.Views.Home.Index&quot; %> <asp:Content ID=&quot;indexContent&quot; ContentPlaceHolderID=&quot;MainContent&quot; runat=&quot;server&quot;> <h2><%= Html.Encode(ViewData[&quot;Message&quot;]) %></h2> <p> To learn more about ASP.NET MVC visit <a href=&quot;http://asp.net/mvc&quot; title=&quot;ASP.NET MVC Website&quot;>http://asp.net/mvc</a>. </p> </asp:Content> Relies on a master page Just displays the data in the ViewData store

<%@ Page Language=&quot;C#&quot; MasterPageFile=&quot;~/Views/Shared/Site.Master&quot; AutoEventWireup=&quot;true&quot; CodeBehind=&quot;Index.aspx.cs&quot; Inherits=&quot;Basic_MVC_Project.Views.Home.Index&quot; %>

<asp:Content ID=&quot;indexContent&quot; ContentPlaceHolderID=&quot;MainContent&quot; runat=&quot;server&quot;>

<h2><%= Html.Encode(ViewData[&quot;Message&quot;]) %></h2>

<p>

To learn more about ASP.NET MVC visit <a href=&quot;http://asp.net/mvc&quot; title=&quot;ASP.NET MVC Website&quot;>http://asp.net/mvc</a>.

</p>

</asp:Content>

Relies on a master page

Just displays the data in the ViewData store

Putting the R in MVC Routing is part of the major power of MVC Many URLs can link to the same controller, unlike code behinds which have a 1-1 link with .aspx pages, controllers can have multiple views Controllers are usually grouped around conceptual objects within the domain Tasks, Posts, Products

Routing is part of the major power of MVC

Many URLs can link to the same controller, unlike code behinds which have a 1-1 link with .aspx pages, controllers can have multiple views

Controllers are usually grouped around conceptual objects within the domain

Tasks, Posts, Products

The ActionResult The key to actions is ActionResult which has many implementations ViewResult: Renders the specified view to the response. EmptyResult: Does nothing. Returned if the action method must return a null result. RedirectResult: Performs an HTTP redirect to the specified URL. RedirectToRouteResult: Given some routing values, uses the routing API to determine the URL and then redirects to that URL. JsonResult: Serializes the specified ViewData object to JSON format. ContentResult: Writes the specified text content to the response.

The key to actions is ActionResult which has many implementations

ViewResult: Renders the specified view to the response.

EmptyResult: Does nothing. Returned if the action method must return a null result.

RedirectResult: Performs an HTTP redirect to the specified URL.

RedirectToRouteResult: Given some routing values, uses the routing API to determine the URL and then redirects to that URL.

JsonResult: Serializes the specified ViewData object to JSON format.

ContentResult: Writes the specified text content to the response.

ActionFilter Attribute based interception of action calls Can hook into calls: OnActionExecuted OnActionExecuting OnResultExecuted OnResultExecuting Useful for logging, security, caching etc.

Attribute based interception of action calls

Can hook into calls:

OnActionExecuted

OnActionExecuting

OnResultExecuted

OnResultExecuting

Useful for logging, security, caching etc.

Extras Ajax made easy You can just return a Json result and JavaScript can eval the response to get the result. REST made easy Routing makes creating rest web services just a case of routing to the correct action

Ajax made easy

You can just return a Json result and JavaScript can eval the response to get the result.

REST made easy

Routing makes creating rest web services just a case of routing to the correct action

Caveats This talk was based on Preview 4, Preview 5 was released on Friday and has a couple of minor changes Preview code still, API’s are subject to change. Still a lot of community work to do to create helpers, utilities etc..

This talk was based on Preview 4, Preview 5 was released on Friday and has a couple of minor changes

Preview code still, API’s are subject to change.

Still a lot of community work to do to create helpers, utilities etc..

Questions? Ask Scott Hanselman……. Contact me: http://www.bgeek.net, owen@bgeek.net, http://www.twitter.com/buildmaster

Ask Scott Hanselman…….

Contact me:

http://www.bgeek.net,

owen@bgeek.net,

http://www.twitter.com/buildmaster

References ASP.net MVC Official Site http://www.asp.net/mvc/ MVC Xerox Parc http://heim.ifi.uio.no/~trygver/themes/mvc/mvc-index.html Scott Gu, Phil Haack, Scott Hanselman, Rob Conery http://weblogs.asp.net/scottgu/ http://haacked.com/Default.aspx http://www.hanselman.com/ http://blog.wekeroad.com/ MVC Contrib Project http://codeplex.com/MVCContrib

ASP.net MVC Official Site http://www.asp.net/mvc/

MVC Xerox Parc http://heim.ifi.uio.no/~trygver/themes/mvc/mvc-index.html

Scott Gu, Phil Haack, Scott Hanselman, Rob Conery http://weblogs.asp.net/scottgu/ http://haacked.com/Default.aspx http://www.hanselman.com/ http://blog.wekeroad.com/

MVC Contrib Project http://codeplex.com/MVCContrib