INTRO TO ASP.NET MVC JAY HARRIS.NET DEVELOPER

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1 INTRO TO JAY HARRIS.NET DEVELOPER

2 WHAT IS MVC? It is a powerful and elegant means of separating concerns There is no universally unique MVC pattern. MVC is a concept rather than a solid programming framework. You can implement your own MVC in any platforms. As long as you stick to the following basic idea, you are implementing MVC: Model: Real world object that provides data to the View View: How to render (UI) Controller: Receives end user request and binds model to the view It promotes parallel development thanks to the loose coupling between the three main components It makes it easier to test application using unit tests

Controller Business logic/validation Code behind or Model Model Initial

3 MVC VS THREE TIERED ARCHITECTURE Functionality Three Tiered Architecture MVC Architecture Look and Feel User Interface View UI logic User Interface Controller Business logic/validation Code behind or Model Model Initial Request User Interface Controller Accessing Data Data Layer Model/Data Access Layer

4 ADVANTAGES OF WEB FORMS Represent a Page as control tree Give ser ver-side controls events like their desktop counterpar ts Hides as much HTTP and HTML as is reasonable Make state management as transparent as possible It supports an event model that preserves state over HTTP, which benefits line-of-business Web application development. The Web Forms-based application provides dozens of events that are supported in hundreds of server controls. It uses a Page Controller pattern that adds functionality to individual pages..net controls allow for rapid application development.

5 WHERE WEB FORMS FALL SHORT ViewState is powerful, but it has its drawbacks (weight, ) Limited control over HTML Client IDs and Master Pages ctl00$contentplaceholder1$usercontrol1$textbox1 enough said Tight coupling of Pages to Codebehind

6 ADVANTAGES OF AN MVC-BASED APPLICATION It makes it easier to manage complexity by dividing an application into the model, the view, and the controller. It does not use view state or server-based forms. This makes the MVC framework ideal for developers who want full control over the behavior of an application. MVC provides better support for test-driven development (TDD). It works well for Web applications that are supported by large teams of developers and for Web designers who need a high degree of control over the application behavior.

7 BELIEFS Guiding tenets: Be extensible, maintainable, and flexible Be testable Get out of the user s way when necessary Serving methods, not files URL routes are defined to target controllers and methods rather than specific aspx pages with load events

8 MVC BEST PRACTICES To effectively use MVC, adhere to the following best practices: The model should be a simple object with read and write properties to support a single view. The view should focus on standards-based markup. Logic in the view should be limited to user interaction and not include business logic. Controllers should not know anything about how the data in the model is manipulated in the view. Controllers should not know anything about how the data is persisted beyond the model.

9 THE MVC PATTERN

10 MODEL The Model represents a set of classes that describes the business logic and data. It also defines business rules for how the data can be changed and manipulated. Models in, handle the Data Access Layer by using ORM tools like Entity Framework or NHibernate etc. Totally independent from the views or the controllers Model state can be stored in memory, database and XML files

11 MODEL EXAMPLE using System; using System.Collections.Generic; using System.ComponentModel.DataAnnotations; namespace Demo.Model { public class Student { public int ID { get; set; public string LastName { get; set; public string FirstMidName { get; set; [DataType(DataType.Date)] [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd", ApplyFormatInEditMode = true)] public DateTime EnrollmentDate { get; set; public vir tual ICollection<Enrollment> Enrollments { get; set;

12 VIEW The View is responsible for transforming a model or models into UI. The Model is responsible for providing all the required business logic and validation to the view. The view is only responsible for displaying the data, that is received from the controller as the result. Views in, handle the UI presentation of data as the result of a request received by a controller. No interaction with the models or the controllers Views can be strongly typed

13 VIEW Layout = ViewBag.Title = "Index"; <h2>index</h2> <p>hello from our View Template!</p>

14 CONTROLLER The Controller is responsible for controlling the application logic and acts as the coordinator between the View and the Model. The Controller receive input from users via the View, then process the user's data with the help of Model and passing the results back to the View. A controller is made up of methods called Action methods which can act as an intermediary between the DAL and return a fully populated view. Controllers in, respond to HTTP requests and determine the action to take based upon the content of the incoming request. Form data from a View can be submitted to a controller s action method as a strongly typed object.

15 CONTROLLER EXAMPLE using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using System.Web.Mvc.Ajax; namespace Demo.Controllers { public class StudentController : Controller { public ActionResult Index() { // Add action logic here return View();

16 PRESERVING DATA offers us three options for preserving data - ViewData, ViewBag and TempData for passing data from controller to view and in next request. ViewData and ViewBag are almost similar and TempData per forms additional responsibility. Difference between ViewBag & ViewData: ViewData is a dictionar y of objects that is derived from ViewDataDictionar y class and is accessible using strings as keys. ViewBag is a dynamic property that takes advantage of the new dynamic features in C# 4.0. ViewData requires typecasting for complex data type and check for null values to avoid error. ViewBag doesn t require typecasting for complex data type. TempData is also a dictionary derived from TempDataDictionary class and stored in short lives session and it is a string key and object value. The difference is the life cycle of the object. TempData keeps the information for the time of an HTTP Request. This mean only from one page to another.

17 FILTERS IN MVC

18 MVC FILTERS IN ACTION The framework supports five different types of filters which are executed in the following order: Authentication filters Used to implement authentication tasks to determine if a user is authenticated before executing the controller action. Authorization filters - Used to implement authorization for authenticated users to determine if a user is authorized to execute the controller action. Action filters - Contain logic that is executed before and after a controller action executes. You can use an action filter, for instance, to modify the view data that a controller action returns. Result filters - Contain logic that is executed before and after a view result is executed. For example, you might want to modify a view result right before the view is rendered to the browser. Exception filters - You can use an exception filter to handle errors raised by either your controller actions or controller action results. You also can use exception filters to log errors.

19 FILTER REGISTRATION Filters can be applied at 3 levels within the application: Global Level Filter is applied to all controller actions within the application Controller Level Filter is applied to all actions within the specific controller. Action Method Level Filter is only applied to an individual action method.

20 AUTHORIZATION FILTER This filter provides authorization logic to determine if a user is authorized to execute the Action method request on the Controller. It will be executed before the action gets executed.

21 AUTHORIZATION FILTER EXAMPLE C o d e : p u b l i c c l a s s C u s t o m A u t h o r i z e A t t r i b u t e : A u t h o r i z e A t t r i b u t e { E n t i t i e s c o n t e x t = n e w E n t i t i e s ( ) ; / / m y e n t i t y p r i v a t e r e a d o n l y s t r i n g [ ] a l l o w e d r o l e s ; p u b l i c C u s t o m A u t h o r i z e A t t r i b u t e ( p a r a m s s t r i n g [ ] r o l e s ) { t h i s. a l l o w e d r o l e s = r o l e s ; p r o t e c t e d o v e r r i d e b o o l A u t h o r i z e C o r e ( H t t p C o n t e x t B a s e h t t p C o n t e x t ) { b o o l a u t h o r i z e = f a l s e ; f o r e a c h ( v a r r o l e i n a l l o w e d r o l e s ) { v a r u s e r = c o n t e x t. A p p U s e r. W h e r e ( m = > m. U s e r I D = = G e t U s e r. C u r r e n t U s e r & & m. R o l e = = r o l e & & m. I s A c t i v e = = t r u e ) ; / / c h e c k i n g a c t i v e u s e r s w i t h a l l o w e d r o l e s. i f ( u s e r. C o u n t ( ) > 0 ) { a u t h o r i z e = t r u e ; / * r e t u r n t r u e i f E n t i t y h a s c u r r e n t u s e r ( a c t i v e ) w i t h s p e c i f i c r o l e * / r e t u r n a u t h o r i z e ; p r o t e c t e d o v e r r i d e v o i d H a n d l e U n a u t h o r i z e d R e q u e s t ( A u t h o r i z a t i o n C o n t e x t f i l t e r C o n t e x t ) { f i l t e r C o n t e x t. R e s u l t = n e w H t t p U n a u t h o r i z e d R e s u l t ( ) ; U s a g e : [ C u s t o m A u t h o r i z e ( A d m i n i s t r a t o r, M o d e r a t o r ) p u b l i c A c t i o n R e s u l t A d d A r t i c l e ( ) { r e t u r n V i e w ( ) ;

22 APPLYING AN EXCEPTION FILTER This filter will be invoked whenever a controller or action of the controller throws an exception. This is par ticularly useful when we need custom error logging module. Filters can be applied globally, to a single action or all actions within a single controller. Example: [HandleError(ExceptionType = typeof(applicationexception), View = "Error")] public class HomeController : Controller { public ActionResult Index() { ViewData["Message"] = "Welcome to!"; return View(); public ActionResult About() { return View();

23 RESULT FILTER This filter will execute before and after the result of the action method has been executed. We can use this filter if we want some modification to be done in the action's result. Example: public class ProfileResultAttribute : FilterAttribute, IResultFilter { private Stopwatch timer ; public void OnResultExecuting(ResultExecutingContext filtercontext) { timer = Stopwatch.Star tnew(); public void OnResultExecuted(ResultExecutedContext filtercontext) { timer.stop(); filtercontext.httpcontext.response.write( string.format( {0 seconds",timer.elapsed.totalseconds));

24 ROUTING IN MVC

25 ROUTING AND SEO Routing is a pattern matching system that monitors the incoming request and determines what to do with that request. At runtime, the routing engine uses the route table for matching the incoming request's URL pattern against the URL patterns defined in the route table. MVCs routing implementation frees up URLs from physical association to a file thus opening up a LOT of flexibility with how URLs can be presented and interpreted in an MVC application. Urls are validated against the route table in sequential order, the first route that matches the url structure will be applied. Routing can be used for SEO to create an intuitive semantic URL to specific page content. Example: Routing Table Entr y: R o u tes.ma proute( n a m e: CustomerLookup, u r l : {control ler/{action/{id, d e f a u l ts: n e w { contro ller = Customers, a c t ion= Lookup, i d = UrlParameter.Optional ) ; Routed URL Breakdown: localhost webserver MVCDev - website Customers Controller Lookup Method 32 Parameter (Customer ID to find)

26 SCAFFOLDING IN MVC

27 WHAT IS SCAFFOLDING? ASP.NET scaffolding is a code generation framework Works with the entity framework to generate pages that are fully functional and include display, insert, edit, delete, sorting and paging functionality (basic CRUD operations) Minimal or no code to create data-driven web applications Quick development time Built-in data validation that is based on the database schema Filters that are created for each foreign key or Boolean fields Utilizes T4 templates which can be created and modified to fit your code generation needs

28 REAL WORLD FINDINGS

29 PROJECT BACKGROUND Took an existing webforms project and converted the most complex user intensive page to MVC. Online calculator that allowed users to request quotes, track resulting information and update budget information. 11 Javascript and 10 CSS files including various plugins and libraries jquery Bootstrap Modernizr 2.6.2

30 PROJECT CODE LINE COUNTS Web Forms UI Code Behind Master Page Web Ser vices Page Total MVC UI Code Behind Master Page Web Ser vices Page Total

31 RENDERING CONTENT Web Forms 2381 lines of html, javascript & css rendered to the browser WebResource.axd (.NET Controls), ScriptResource.axd (AJAX) &.NET Toolkit Combined Scripts Viewstate MVC 1017 lines of html, javascript & css rendered to the browser Minified css & js Razor syntax allowed for streamlined html content No Viewstate

32 JAVASCRIPT BUNDLING WebForms MVC Script Async Time Script Async Time Jquery.js 42ms Jquery (jquery & jquery ui) 33ms WebResource.axd 38ms Bootstrap 33ms ScriptResource.axd 39ms Functions 33ms Bootstrap.js Plugins.js Modernizr.js 44ms 43ms 47ms Js (plugins, main, moment, jquery.cookie, jquery.browser, modernizr) 32ms Jquery.browser 48ms Functions.js 52ms Moment.js 52ms Main.js 51ms Jquery.cookie 50ms Jquery.ui 52ms Calculator?CombinedScripts 89ms

33 CSS BUNDLING WebForms MVC CSS Async Bundle Async Bootstrap 30ms Font-awesome 49ms Bootstrap-theme 31ms Css?fontfamily 80ms Font-awesome Fuelux Custom 245ms 33ms 33ms Style (bootstrap, bootstrap-theme, fuelux, main, custom, spinner, jquery-ui, jquery-ui.theme) 35ms Spinner 34ms Css?fontfamily 85ms Main.css 33ms Jquery-ui 35ms Jquery-ui.theme 35ms

34 PROJECT OUTCOME Page Body Content (Bytes) HTML Line Counts (Lines) ASP.NET Webforms (31,646 bytes) MVC (12,911 bytes) ASP.NET Webforms (2,381 lines) MVC (1,017 lines)

35 PROJECT OUTCOME Page Load Time (ms) A JAX Callback Sizes (Bytes) ASP.NET Webforms (995ms) MVC (620ms) ASP.NET Webforms (248kb) MVC (82kb)

36 Q & A

Working with Controllers

Controller 1 Objectives 2 Define and describe controllers Describe how to work with action methods Explain how to invoke action methods Explain routing requests Describe URL patterns Working with Controllers