AMS304: Introduction to the ASP.NET Model View Controller (MVC) Framework Scott Hanselman Eilon...

AMS304: Introduction to the ASP.NET Model View Controller

(MVC) Framework

Scott Hanselman Eilon Lipton

Microsoft Microsoftscottha@microsoft.com elipton@microsoft.com

INTROMVC

Goodness

• Maintain Clean Separation of Concerns● Easy Testing ● Red/Green TDD ● Highly maintainable applications by default

• Extensible and Pluggable● Support replacing any component of the

system

Goodness

• Enable clean URLs and HTML● SEO and REST friendly URL structures

• Great integration within ASP.NET● Support both static and dynamic languages

What’s the Point?

• This is not Web Forms 4.0● It’s about alternatives. Car vs. Motorcycle.

• Simple or as complex as you like● Extend it, add IOC. Or not. If the shoe pinches, don’t

wear it.

• Fundamental● Part of System.Web and isn’t going anywhere.

• Plays Well With Others● Feel free to use NHibernate for Models, Brail for

Views and Whatever for Controllers. Be Happy.

MVC

Model

ControllerView

A Little More Detail

Model

ControllerView

• Browser requests /Products/• Route is determined• Controller is activated• Method on Controller is invoke• Controller does some stuff• Renders View, passing in

custom ViewData• URLs are rendered,

pointing to other Controllers

Even More Detail – Request Flow

• You can futz at each step in the process

Request

Demo – Hello MVC World

Don’t fall asleep, it’ll be worth it.

HOW IT WORKSMVC

Basic Controller Handling

• Scenarios, Goals and Design● URLs route to controller “actions”, not pages –

mark actions in Controller.● Controller executes logic, chooses view.

[ControllerAction] public void ShowPost(int id) { Post p = PostRepository.GetPostById(id); if (p != null) { RenderView("showpost", p); } else { RenderView("nosuchpost", id); }}

Basic Views

• Scenarios, Goals and Design:● Are for rendering/output.

• Pre-defined and extensible rendering helpers

● Can use .ASPX, .ASCX, .MASTER, etc.● Can replace with other view technologies:

• Template engines (NVelocity, Brail, …).• Output formats (images, RSS, JSON, …).• Mock out for testing.

● Controller sets data on the View• Loosely typed or strongly typed data

URL Routing – Pretty URIs• Developers adds Routes to a global RouteTable• Mapping creates a RouteData - a bag of key/values

protected void Application_Start(object sender, EventArgs e) {

RouteTable.Routes.Add(new Route { Url = "Blog/bydate/[year]/[month]/[day]", Defaults = new { controller="blog", action="showposts" }, Validation = new { year=@"\d{1,4}", month= @"\d{1,2}", day = @"\d{1,2}"} });

RouteTable.Routes.Add(new Route { Url = "[controller]/[action]/[id]", RouteHandler = typeof(MvcRouteHandler) });

}

Demo – Routing

The route less travelled…

HOW TO TEST ITMVC

Interfaces and TDD

• Mockable Intrinsics● IHttpContext, IHttpResponse, IHttpRequest

• Extensibility ● IController● IControllerFactory● IRouteHandler● IView● IViewFactory

Testing Controller Actions

• No requirement to mock out full ASP.NET runtime.[TestMethod]public void ShowPostsDisplayPostView() { TestPostRepository repository = new TestPostRepository(); TestViewFactory viewFactory = new TestViewFactory();

BlogController controller = new BlogController(…); controller.ShowPost(2);

Assert.AreEqual("showpost", viewFactory.LastRequestedView); Assert.IsTrue(repository.GetPostByIdWasCalled); Assert.AreEqual(2, repository.LastRequestedPostId);}

Controller Factory

• Scenarios, Goals and Design:● Hook creation of controller instance

• Dependency Injection.• Object Interception.

public interface IControllerFactory { IController CreateController(IHttpContext context, RouteData routeData, Type controllerType);}

protected void Application_Start(object s, EventArgs e) { ControllerBuilder.Current.SetDefaultControllerFactory( typeof(MyControllerFactory));}

View Factory

• Scenarios, Goals and Design:● Mock out views for testing● Replace ASPX with other technologies

public interface IViewFactory { IView CreateView(IHttpContext context, RouteData routeData, string viewName, string layoutName, object viewData); }

Inside controller class: ViewFactory = new XmlViewFactory(...);

RenderView("foo", myData);

Demo – TDD

Wasn’t this demo technically supposed to be first?

Demo – Dynamic Data Controls

Not DDE. Scared you, didn’t I?

Demo – ImageGen

It’s your thing. Do what you wanna do.

Demo – Ruby View Engine& Python Controller

It’s a kinder, gentler Microsoft.No seriously. Hug?

Demo – XML-RPC

SOAP is for dorks.

Conclusion

• This is not Web Forms 4.0● It’s about alternatives. Car vs. Motorcycle.

• Simple or as complex as you like● Extend it, add IOC. Or not. If the shoe pinches, don’t

wear it.

• Fundamental● Part of System.Web and isn’t going anywhere.

• Plays Well With Others● Feel free to use NHibernate for Models, Brail for

Views and VB for Controllers. Be Happy.

Your Feedback is Important

Please fill out a session evaluation form and either put them in the basket near the exit

or drop them off at the conference registration desk.

Thank you!