Virtual techdays INDIA │ 22-24 November 2010 ASP.Net MVC Deep Dive Sundararajan S │ Associate...

virtual techdaysINDIA │ 22-24 November 2010

ASP.Net MVC Deep Dive

Sundararajan S │ Associate Tech Architect, Aditi Technologies

Asp.Net MVC Request Processing Routing

Introduction Understanding the Routing process Writing your custom Route Writing your Custom RouteHandler

Controller Action Methods Action Results Writing your own Custom ActionResult Filters CustomFilters Asynchronous Controllers


S E S S I O N A G E N D A

ASP.Net MVC Request Processing Architecture

Incoming HTTP Request

IIS / ASP.Net

URL Routing ModuleServe the file directly

Matching file on disk

RouteTable.RoutesIRouteHandler

IHttpHandler

MVCRouteHandler

ControllerFactoryIController

Custom controller factory

ActionMethodWrites directly to http response

Return ActionResult

Is A ViewResult?

Not A ViewResult?

ActionResult.Execute

Routing

Controller/ Actions

ASP.Net MVC Request Processing Architecture

View Engine

WebForm - .Aspx

Render View

Custom View Engine

Views

URLs are not expected to correspond to a Physical File Routes are configured

Maps each incoming URL to appropriate Request handler Class Constructs outgoing URLs

Routing Module is shared between both Asp.Net MVC and Asp.Net web forms System.web.Routing dll in Asp.Net 3.5 System.Web.dll in Asp.Net 4.0

Routing

Introduction

Routes are configured in Global.asax

Routing

Setting up Routes

Routing

System.Web.Routing.Route

Property Meaning Type Example

Url URL to be matched String “Blog/{blogID}”

RouteHandler Existing or custom route handler

IRouteHandler

new MVCRouteHandler()

Default Default Value for the parameter / Optional Parameters

RouteValueDictionary

Constraints Specify constraints on the Route parameters


DataTokens Other Route values that can be accessed during Routing


Areas.

Three main elements RouteBase Route RouteCollection [RouteTable.Routes]

Routing

Understanding the Routing

Routing

Routing Process

Url requested by the end user

Registered iHttpModules get invoked.UrlHttpModule gets invoked

First RouteBase object that matches this request in RouteTable.Routes is identified

Fetches the RouteData data Structure from the Matching Route [route , routehandler, values, datatokens]

Invoke RouteData ‘s RouteHandler

Create a new class that derives from RouteBase Implement GetRouteData(HttpContextBase httpContext)

Framework calls this method on each routetable data entry until one of them returns non null value

Return a routeData structure describing the chosen IRouteHandler Implement GetVirtualPath(RequestContext context, RouteValueDictionary

values) Outbound URL generation Framework calls this method on each routetable data entry until one of them returns non

null value

Routing

Custom Route


DEMO: Custom Route

Sundararajan S│ Assoc. Tech Architect, Aditi

Create new HttpHandler by implementing the interface IHttpHandler Implement the process request method of IHttpHandler Implement the interface IRouteHandler Implement GetHttpHandler(RequestContext requestContext)

Return the HttpHandler Created in the first step

Routing

Custom RouteHandler


DEMO: Custom RouteHandler


Any incoming request is handled by the Controller

Controller

Introduction

IController

Custom ControllerSystem.Web.MVC.

Controller

HomeController (app specific controllers)

AccountController(app specific controllers)

Implements IController Abstracts the Execute Method Following features

Action Methods Action results Filters

Controller

System.Web.MVC.Controller

Filter

ActionMethod

ActionResult

Three ways to read the input in the Action method Read Values from context objects Parameters to Action methods Model Binding

Commonly used Context objects Request - .QueryString, .Form, .Cookies, .HttpMethod, .Headers, .Url, .UserHostAddress RouteData - .Route, .Values User TempData HttpContext -.Application, .Cache, .Items, .Session

Controller

Reading Input

Parameter objects are instantiated using Value Providers and Model Binders

Value type parameters are inherently compulsory To make them optional – 1. specify a default value (or) 2. make them nullable (double?)

Reference Parameters are inherently optional To make them compulsory, check for the null value and throw exception using custom

code. Default Values for parameters

.Net 3.5 – Mark the parameter with the attribute [DefaultValue()] .Net 4.0 – Use optional parameter syntax

ActionMethods cannot have out/ref parameters

Controller

ActionMethod Parameters

Main types of responses Retun HTML by rendering a view

ViewResult , PartialViewresult

Redirect page – HTTP Redirection RedirectToRouteResult, RedirectResult

Other data to the responses output stream ContentResult, JsonResult, JavascriptResult, FileResult, HTTPUnAuthorizedresult, EmptyResult

All Action Results derive from Action Result All Action results have a method – ExecuteResult() This is an example of command pattern

Controller

ActionResult

ViewData Dictionary KeyValue pair To pass data from the actionmethod to the view

Strongly type Model ViewData.Model Create a strongly type view page

Dynamic object in .Net 4.0 ViewPage<dynamic>

TempData[“key”] to share data across redirections

Controller

Sharing Data

Inherit from ActionResult Class Override ExecuteResult (ControllerContext context)

Controller

Custom ActionResult


DEMO: Custom ActionResult


Attach extra behaviors to controllers and actions .Net Attribute Based Four types of filters

Controller

Filters – Attach reusable behaviors

Filter Type Interface When Run Default Implementation

Authorizationfilter IAuthorizationFilter First AuthorizeAttribute

Action Filter IActionFilter Before and after action method

ActionFilterAttribute

ResultFilter IResultFilter Before and after action result is executed

ActionFilterAttribute

Exception filter IExceptionFilter Unhandled Exception HandleErrorAttribute

IActionFilter OnActionExecuting() – Before that Action method runs OnActionExecuted() – After the Action method Runs

IResultFilter OnResultExecuting() –Before the actionResult is executed OnResultExecuted() – After the actionResult is executed

Controller

Filters – Custom Action and Result Filters


DEMO: Custom Action Filter


Three ways to build Asynchrony in Asp.Net MVC RouteHandler ‘s GetHttpHandler() returns a type of IHttpAsyncHandler

Works directly with underlying core platform Bypasses ASP.Net MVC

Create a custom Controller type , that implements IAsyncController Inherit your controller from AsyncController

Inherit from AsyncController Create two methods for every action 1. <ActionMethodName>Async 2. <ActionMethodName>Completed

Controller

Asynchronous Requests

Controller

Asynchronous Requests

Increment the outstanding operations

Mark that FetchScoreCompleted can be called

Set the parameters for the Completed Method


DEMO: Asynchronous Controllers



RESOURCES

Asp.Net MVC http://www.asp.net/mvc

Apress – Pro Asp.Net MVC2 Framework by Steven Sanderson

virtual techdaysTHANKS│ 22-24 November 2010

[email protected] │ http://sundars.nethttp://www.codeshelve.com http://tinyurl.com/codeshelve

http://sundars.net/

http://www.codeshelve.com/

http://tinyurl.com/codeshelve

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