Asp.Net Mvc Internals & Extensibility

MVC Internals & Extensibility

Eyal VardiCEO E4D Solutions LTDMicrosoft MVP Visual C#blog: www.eVardi.com

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Agenda

Routing

Dependency Resolver

Controller Extensibility

Model Extensibility

View Extensibility


MVC in ASP.NET


MVC Execution ProcessASP.NET

IIS Routing ASP.NET MVC 3.0


URL Routing

http://Domain/Path

http://Domain/.../..

URL to Controller

URL to Page


Routes A route is a URL pattern that is mapped to a

handler. The handler can be a physical file, such as an .aspx file in a

Web Forms application. A handler can also be a class that processes the request,

such as a controller in an MVC application.

protected void Application_Start(){ RouteTable .Routes .MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL template new { controller="Calc", action="Add", id=UrlParameter.Optional } );}

Global.asax


Route lifecycle


Route

IDependencyResolver

MvcRouteHandler MvcHandler Controller

Routing Process


URL PatternsRoute definition Example of matching URL

{controller{/}action{/}id } /Products/show/beverages {table/}.Details aspx /Products/Details.aspx

blog/{action}/{entry} /blog/show/123 {reporttype{/}year{/}month{/}day } /sales/2008/1/5

{locale{/}action } /US/show {language{-}country{/}action } /en-US/show


URL Patterns in MVC Applications

{Controller} / {Action} / {id}

Query / {queryname} / {*queryvalues} “*” This is referred to as a catch-all parameter.

/query/select/bikes/onsale queryname = "select" , queryvalues = "bikes/onsale"


Adding Constraints to Routes Constraints are defined by using regular

expressions string or by using objects that implement the IRouteConstraint interface.

protected void Application_Start(){ RouteTable .Routes .MapRoute( "Blog", "Posts/{postDate}", new { controller="Blog",action="GetPosts" } );}

/Posts/28-12-71 => BlogController,GetPosts( “28-12-1971” )/Post/28 => BlogController,GetPosts( “28” )/Post/test => BlogController,GetPosts( “test” )

Global.asax


IRouteConstraintprotected void Application_Start(){ RouteTable .Routes .MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL template new { controller="Calc", action="Add", id=UrlParameter.Optional }, new { action = new MyRouteConstraint() } );} Custom Route Constraint

Global.asax


Regular Expression Route Constraint

protected void Application_Start(){ RouteTable .Routes .MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL template new { controller="Calc", action="Add", id=UrlParameter.Optional }, new { action = @"\d{2}-\d{2}-\d{4}" } );} Regular Expression


Custom Route Constraint


Dependency Resolver Service locator for the framework.

protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes);

DependencyResolver .SetResolver(new TraceDependencyResolver() ); }


Factories and Providers


Dependency Resolver


Controller Extensibility


Controller & Filters The Controller class implements each of the

filter interfaces. You can implement any of the filters for a

specific controller by overriding the controller's On<Filter> method. OnAuthorization OnActionExecuting OnActionExecuted OnResultExecuting OnResultExecuted OnException


Action Method Action Result


ASP.NET MVC Filters Filters are custom classes that provide both a

declarative and programmatic means to add pre-action and post-action behavior to controller action methods.

[HandleError] [Authorize]public class CourseController : Controller{ [HandleError] [OutputCache] [RequireHttps] public ActionResult Net( string name ) { ViewBag.Course = BL.GetCourse(name); return View(); }}


IAuthorizationFilter Make security decisions about whether to

execute an action method. AuthorizeAttribute

RequireHttpsAttribute


IActionFilter Interface OnActionExecuting

Runs before the action method.

OnActionExecuted Runs after the action method


IResultFilter Interface OnResultExecuting

Runs before the ActionResult object is executed.

OnResultExecuted Runs after the result. Can perform additional processing of the result. The OutputCacheAttribute is one example of a result filter.


IExceptionFilter Execute if there is an unhandled exception

thrown during the execution of the ASP.NET MVC pipeline. Can be used for logging or displaying an error page.

HandleErrorAttribute is one example of an exception filter.


Filter Order Filters run in the following order:

Authorization filters

Action filters

Response filters

Exception filters


Controller Context1

2 3 4 5

6


Filters


Custom Filter You can create a filter in the following ways:

Override one or more of the controller's On<Filter> methods.

Create an attribute class that derives from ActionFilterAttribute or FilterAttribute.

Register a filter with the filter provider (the FilterProviders class).

Register a global filter using the GlobalFilterCollection class.


Custom Filter


Filter Providers By default, ASP.NET MVC registers the

following filter providers: Filters for global filters.

FilterAttributeFilterProvider for filter attributes.

ControllerInstanceFilterProvider for controller instances.

The GetFilters method returns all of the IFilterProvider instances in the service locator.


The Filter Provider Interface


Model Extensibility


Model Binders Binders are like type converters, because they

can convert HTTP requests into objects that are passed to an action method.



Model Binder Types

ByteArrayModelBinder

LinqBinaryModelBinder

FormCollectionModelBinder

HttpPostedFileBaseModelBinder

DefaultModelBinder


DefaultModelBinder Class Translate HTTP request

information into complex models, including nested types and arrays. It does this through a naming

convention, which is supported at both the HTML generation (HTML helpers) and the consumption side (model binders).


Custom Model Binders ASP.NET MVC allows us to override both the

default model binder, as well as add custom model binders.

ModelBinders.Binders.DefaultBinder = new CustomDefaultBinder();

ModelBinders.Binders.Add( typeof(DateTime),

new DateTimeModelBinder() );


ModelBinder Attribute Represents an attribute that is used to

associate a model type to a model-builder type.

public ActionResult Contact( [ModelBinder(typeof(ContactBinder))] Contact contact ){ ViewData["name"] = contact.Name; ViewData["email"] = contact.Email; ViewData["message"] = contact.Message; ViewData["title"] = "Succes!";

return View();}


Custom Binder


public ActionResult Contact( [ModelBinder(typeof(ContactBinder))] Contact contact ){ ViewData["name"] = contact.Name; ViewData["email"] = contact.Email; ViewData["message"] = contact.Message; ViewData["title"] = "Succes!";

return View();}


View Extensibility




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Asp.Net Mvc Internals & Extensibility