This document provides an overview of ASP.net MVC, including what MVC is, how ASP.net MVC request execution works, details on controllers, routing, application development, differences from web forms, and when to use MVC. It describes MVC as separating applications into models, views, and controllers, and how ASP.net MVC implements the MVC pattern with controllers handling user input and selecting views. Request processing and controller lifecycles are also summarized at a high level.

1. ASP.net MVC
Overview
-Divya Sharma

2. Agenda
 What is MVC?
 ASP .net MVC Request Execution
 Controller in Detail
 ASP .net Routing
 Application Development and Code walkthrough
 ASP .net Web forms v/s ASP .net MVC
 Q&A

3. What is MVC?
 MVC (Model-View-Controller) is an
architectural pattern for web based
applications.
 The application is separated among
Model, View and Controller which
provides a loose coupling among
business logic, UI logic and input logic.
 ASP.net MVC framework provides an
alternative to ASP.net web forms for
building ASP.net web applications.

4. Features of MVC
 Separation of application tasks viz. business logic, UI
logic and input logic
 Supports Test Driven Development (TDD)
 Highly testable framework
 Extensible and pluggable framework
 Powerful URL-mapping component for comprehensible
and searchable URLs
 Supports existing ASP.net features viz. authentication,
authorization, membership and roles, caching, state
management, configuration, health monitoring etc.

5. Model
 Model objects are the parts of the application that
implement the logic for the application’s data domain.
Often, model objects retrieve and store model state in a
database.
 For example, a Product object might retrieve information
from a database, operate on it, and then write updated
information back to a Products table in SQL Server.
 In small applications, the model is often a conceptual
separation instead of a physical one.

6. View
 Views are the components that display the application’s
user interface (UI). Typically, this UI is created from the
model data.
 An example would be an edit view of a Products table
that displays text boxes, drop-down lists, and check
boxes based on the current state of a Products object.

7. Controller
 Controllers are the components that handle user
interaction, work with the model, and ultimately select a
view to render that displays UI. In an MVC application,
the view only displays information; the controller handles
and responds to user input and interaction.
 For example, the controller handles query-string values,
and passes these values to the model, which in turn
queries the database by using the values.

8. MVC Request Execution
RouteData MvcHandler
Request object Object
UrlRoutingModule
MvcRouteHandler Controller
(Http Module)
Response Result Type Result Type
object object
The UrlRoutingModule and MvcRouteHandler classes are
the entry points to the ASP.NET MVC framework. They
perform the following actions:
 Select the appropriate controller in an MVC Web
application.
 Obtain a specific controller instance.
 Call the controller's Execute method.

9. Stages of Request Execution
Stage Details
first request for In the Global.asax file, Route objects are added to the RouteTable object.
the application
Perform routing The UrlRoutingModule module uses the first matching Route object in the RouteTable
collection to create the RouteData object, which it then uses to create a
RequestContext object.
Create MVC The MvcRouteHandler object creates an instance of the MvcHandler class and passes
request handler the RequestContext instance to the handler.
Create The MvcHandler object uses the RequestContext instance to identify the
controller IControllerFactory object (typically an instance of the DefaultControllerFactory class) to
create the controller instance with.
Execute The MvcHandler instance calls the controller's Execute method.
controller
Invoke action For controllers that inherit from the ControllerBase class, the ControllerActionInvoker
object that is associated with the controller determines which action method of the
controller class to call, and then calls that method.
Execute result The action method receives user input, prepares the appropriate response data, and
then executes the result by returning a result type. The built-in result types that can be
executed include the following: ViewResult (which renders a view and is the most-often
used result type), RedirectToRouteResult, RedirectResult, ContentResult, JsonResult,
FileResult, and EmptyResult.

10. Controllers and ActionResult
// action methods that render view pages // HelloWorld action method
URL = Home/Index and Home/About with value for view data.
URL = Home/HellowWorld
[HandleError]
public class
public class HomeController : Controller
HomeController : Controller
{
{
public ActionResult Index()
[ControllerAction]
{
public ActionResult
ViewData["Msg"] = "Welcome" ; HelloWorld()
return View(); {
ViewData["Message"] = "Hello
}
World!";
public ActionResult About()
return View();
{
}
return View();
}
}
}

11. Controllers and ActionResult
// non action method // optional arguments for action method
e.g. URL = Products/ShowProduct/P1?23 or
[NonAction]
URL = Products/ShowProduct/P1?23
private void DoSomething()
public ActionResult ShowProduct(string
{ category, int? id)
// Method logic. {
} if(!id.HasValue)
{
// use Request object to
retrieve query string value id = 0;
public void Detail() }
{ // ...
int id = }
Convert.ToInt32(Request["id
"]);
}

12. ActionResult Type
Action Result Helper Method Description
ViewResult View Renders a view as a Web page.
PartialViewResult PartialView Renders a partial view, which defines a
section of a view that can be rendered
inside another view.
RedirectResult Redirect Redirects to another action method by using
its URL.
RedirectToRouteResult RedirectToAction Redirects to another action method.
RedirectToRoute
ContentResult Content Returns a user-defined content type.
JsonResult Json Returns a serialized JSON object.
JavaScriptResult JavaScript Returns a script that can be executed on the
client.
FileResult File Returns binary output to write to the
response.
EmptyResult (None) Represents a return value that is used if the
action method must return a null result
(void).

13. ASP .net Routing
 The ASP.NET Routing module is responsible for mapping incoming
browser requests to particular MVC controller actions.
 Default URL format: controller/action/parameters
 ASP.NET Routing is setup in two places in the application:
 Web.config – uses 4 sections viz. system.web.httpModules,
system.web.httpHandlers, system.webserver.modules,
system.webserver.handlers
 Global.asax.cs – Routes are provided and registered on
Application_Start event.

14. Route Table in Global.asax.cs
public class MvcApplication : System.Web.HttpApplication
{
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute( "Default", // Route name "{controller}/{action}/
{id}", // URL with parameters
new { controller = "Home", action = "Index", id = "" } // Params
);
}
protected void Application_Start()
{
RegisterRoutes(RouteTable.Routes);
}
}

15. Setting Default Values of
URL Parameters
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapPageRoute("", "Category/{action}/{categoryName}",
"~/categoriespage.aspx", true, new RouteValueDictionary
{{"categoryName", "food"}, {"action", "show"}});
}
URL Parameter values
/Category action = "show" (default value)
categoryName = "food" (default value)
/Category/add action = "add"
categoryName = "food" (default value)
/Category/add/beverages action = "add"
categoryName= "beverages"

16. Adding Constraints to Routes
public static void RegisterRoutes(RouteCollection routes)
{
routes.MapPageRoute("", "Category/{action}/{categoryName}",
"~/categoriespage.aspx", true, new RouteValueDictionary
{{"categoryName", "food"}, {"action", "show"}}, new
RouteValueDictionary {{"locale", "[a-z]{2}-[a-z]{2}"},{"year",
@"d{4}"}} );
}
URL Result
/US No match. Both locale and year are required.
/US/08 No match. The constraint on year requires 4
digits.
/US/2008 locale = "US"
year = "2008"

17. Basic ASP .net MVC
Application Development
Prerequisites –
 Microsoft Visual Studio 2008 Service Pack 1 or later
 The ASP.NET MVC 2 framework (For Microsoft Visual
Studio 2010 this framework comes in the package)
Video :
http://www.asp.net/mvc/videos/creating-a-movie-database-application-in-15-minutes-with-aspnet-mvc

18. ASP .net MVC Project Structure
 There can be multiple views for a
controller
 Name of controller must have
‘Controller’ suffix
 Name of page is not necessarily
part of the URL
 There can be multiple routes
defined for an application and
URL matching is done in order.

19. Code Walkthrough
 http://weblogs.asp.net/scottgu/archive/2007/11

20. Advantages of MVC Based
Web Application
 Complex applications are easy to manage with divisions
of Model, View and Controllers.
 Provides strong routing mechanism with Front Controller
pattern.
 More control over application behavior with elimination of
view state and server based forms
 Better support for Test Driven Development (TDD)
 Works well for development with large teams with
multiple web developers and designers working
simultaneously.

21. Advantages of Web Forms Based
Web Application
 Supports an event model that preserves state over
HTTP, which benefits line-of-business Web application
development.
 Adds functionality to individual pages with Page
Controller pattern.
 Managing state information is easier with use of view
state and server-based forms.
 Less complex for application development with tightly
integrated components.
 Works well for small teams of web developers and
designers who want to take advantage of the large
number of components available for rapid application
development.

22. ASP .net Web Forms v/s
ASP .net MVC
Feature ASP .net Web Forms ASP .net MVC
Separation of concerns Less More
Style of programming Event-driven Action result based
Request execution Event based Controller based
Complexity of state management Less More; does not support
view state
Control on application behavior Less More
(Rendered HTML)
Availability of controls In abundance + third party Less
Support for server controls Yes No
Support for ASP .net features like Yes Yes
authentication, authorization, roles,
configuration, etc.
Support for TDD No Yes
Ease of application development More Less
Application maintainability Less More

23. When to Use ASP .net MVC?
 ASP .net MVC is NOT a replacement of ASP .net web
forms based applications.
 The approach of application development must be
decided based on the application requirements and
features provided by ASP .net MVC to suite them.
 Application development with ASP .net MVC is more
complex as compared to web forms based applications
with lack of readily available rich controls and less
knowledge of the pattern in ASP .net web developers.
 Application maintainability will be higher with separation
of application tasks.

24. References
 http://www.asp.net/mvc
 http://msdn.microsoft.com/en-us/library/dd394709.aspx
 http://weblogs.asp.net/scottgu/archive/2007/11/13/asp-net-mv
 http://weblogs.asp.net/scottgu/archive/2007/12/03/asp-net-mv

25. Q&A

26. Thanks!