One of the best features of ASP.NET MVC is that it's totally extensible: if you don't like the way the framework works or if you have scenarios not covered by it, you can change the behaviors by extending the defaults or by writing your owns. In this presentation I'll go through all the main extensibility points and explain how to leverage the main ones

1. Extending ASP.NET MVC Part 1 Simone ChiarettaArchitect, Council of the EU http://codeclimber.net.nz Twitter: @simonech June 23rd, 2010

2. Who the hell am I? Simone Chiaretta Microsoft MVP ASP.NET ASP Insider Blogger – http://codeclimber.net.nz ItalianALT.NET UG Founder OpenSource developer Climber All Around Nice Guy Disclaimer:"The viewsexpressed are purelythose of the speaker and may not in anycircumstancesberegarded as stating an official position of the Council"

3. Agenda The default ASP.NET MVC Pipeline Extensibilitypoints’ list The Mostimportantextensibilitypoints

4. The DefaultASP.NET MVC Pipeline

5. The default ASP.NET MVC Pipeline 4

6. The default components URL Routing: Parses the URL, andinstantiate the MvcHandler Controller Factory Takes URL parameters, create controller via reflectionbased on Controllername Action Invoker Invokes the actionbased on thename, with the filtersbefore and after ViewEngine WebFormsviewengine Template Renders a TextBoxalmostforeverything HtmlHelper Has a bunch of standardmethods

7. ASP.NET MVC IS extensible Ifyou don’t likethem Ifyouneedsomething else Changethem

8. ASP.NET MVC IS extensible Almosteveryaspectof the framework can beextented/replaced

9. Extensibilitypoints’ list

10. Routingextensibility RouteConstraint Validatesrouteparameterswith code RouteHandler Defineshow the requestmustbehandled

11. Controller Extensibility ControllerFactory ResponsibleforcreatingControllers ActionInvoker Invokesanaction, basedonly on itsname ActionMethodSelectorAttribute Helps the actioninvoker decide whichactiontoinvokewhen the nameisnotunique Controller The base classforevery controller ActionResult Decideshowtosend the output to the user

12. ActionFilterExtensibility AuthorizationFilter Makessure the currentrequestisallowed ActionFilters Executedbefore or after the actionexecutes ResultFilters Executedbefore or afteranactionresultexecutes

13. Binding/ValidationExtensibility ModelBinder Populates the actionmethodparametersfrom the request ModelValidator Provider Retrieves the validationrules Server-sideValidationRules The actual server-side validationrule

14. ViewExtensibility ViewEngine The service thattransforms in HTML the data for the user HtmlHelpers Utility functionsthathideaway the generation of some HTML markup or JavaScript code Client-sideValidationRules Client-sidevalidationrules ModelMetadata Provider Retrieves the metadataneededfor the templatedhelpers Custom Templates Renders the html toedit/display specifictypes

15. The Mostimportantextensibilitypoints

16. The MostimportantExtensibilitpoints The onesyouwilldefinitelyuse The onesyouhaveto start using The onesyoumight or mightnotneedtouse The onesyoumostlikelywillnotwriteyourself butprobablyusewrittenbyothers

17. Extensibilitypointsyouwilluse

18. CustomTemplates

20. CustomTemplates AddPartialViews in: /Views/Shared/DisplayTemplates /Views/Shared/EditorTemplates Demo

21. Server-sideValidationRules

22. Server-sideValidationRules WHAT: Definehow a propertyisvalidated in the server side validation DEFAULT: Required, Length, wrong type WHY: Addyourownrules

23. Server-sideValidationRules Write a newValidationAttribute Implement the IsValidmethod Applyattributetoyourmodel Demo

24. Client-sideValidationRules

25. Client-sideValidationRules WHAT: Definehow a propertyisvalidated in the client-side validation DEFAULT: Client-sidecounterparts of the default server-side validators WHY: Addyourownvalidators

26. Client-sideValidationRules First make a server-side validator Makevalidationlogic in JavaScript Writeadaptertopushvalidationrulesto client-side Registervalidationfunction via JS Registeradapter in Global.asax Demo

27. Extensibilitypointsyouhaveto start using

28. Base Controller

29. Base Controller WHAT: The base class forevery Controller DEFAULT: Defaultimplementation of helpermethods WHY: Extendifyouwanttoenforceyouownconventions

30. Base Controller Override Controller YourcontrollersoverridefromBaseControllerinsteadof Controller Demo

31. HtmlHelpers

32. HtmlHelpers WHAT: Utility functionsthathideaway the generation of HTML markup or JavaScript code DEFAULT: Html.TextBox, Html.Encode, Html.Partial, … WHY: “Ifthereisanif, writeanHelper”

33. HtmlHelpers Add new methodsasextensionmethods Demo

34. Rating If you liked this talk, please consider rating it: http://speakerrate.com/talks/3669-asp-net-mvc-extensibility 33 Disclaimer:"The viewsexpressed are purelythose of the speaker and may not in anycircumstancesberegarded as stating an official position of the Council"

35. Extending ASP.NET MVC Part 2 Simone ChiarettaArchitect, Council of the EU http://codeclimber.net.nz Twitter: @simonech June 23rd, 2010

36. Filters

37. AuthorizationFilter WHAT: Makes sure the current request is allowed DEFAULT: Itisbased on the ASP.NETMembership provider WHY: ChangeifyouwantnottouseASP.NET MVC or ifyouwanttoenhance the routedictionary

38. Action Filters WHAT: Executed before or after the action executes DEFAULT: Output cache WHY: Addyourownbased on yourneeds

39. ResultFilters WHAT: Executed before or after an action result executes DEFAULT: No default resultfilters WHY: Addyourownbased on yourneeds

40. AuthorizationFilter ImplementIAuthorizationFilter OnAuthorization

41. Filters ImplementIActionFilter + IResultFilter MakenewActionFilterAttribute OnActionExecuting OnActionExecuted ImplementIResultFilter OnResultExecuting OnResultExecuted

42. Extensibilitypointsyoumightwanttouse

43. RouteConstraint

44. RouteConstraint WHAT: Validates route parameters DEFAULT: No default implementation WHY: Addyourownwhenneeded

45. RouteConstraint Implement IRouteConstraint.Match Inspectrequest and returntrue or false Demo

46. RouteHandler

47. RouteHandler WHAT: Defineshow the requestmustbehandled DEFAULT: Routes the requesttoMvcHandler WHY: ChangeifyouwantnottouseASP.NET MVC

48. RouteHandler Implement IRouteHandler.GetHttpHandler Demo

49. ActionMethodSelectorAttribute

50. ActionMethodSelectorAttribute WHAT: Helps the action invoker decide which action to invoke when the name is not unique DEFAULT: HttpMethod attributes: decide based on the HttpMethod WHY: Addyourowntosupportdifferentscenarios

51. ActionMethodSelectorAttribute Create newAttibuteinheritingfrom ActionMethodSelectorAttribute Implement: IsValidForRequest Demo

52. ActionResult

53. ActionResult WHAT: Sends the output to the user DEFAULT: ViewResult, RedirectResult, FileResult, JsonResult, etc… WHY: Addyourownifyouneedan output notavailable in the default results

54. ActionResult Create a new resultinheritingfrom: ActionResult Implement: ExecuteResult Optionally create anhelpermethod in you “base controller” Demo

55. ModelBinder

56. ModelBinder WHAT: Populates the action method parameters from the request DEFAULT: Bindsrequest’s valuesbased on names WHY: Extendifyouneedtoaddother way ofbinding

57. ModelBinder ImplementIModelBinder BindModel InheritfromDefaultModelBinder BindProperty OnModelUpdated OnModelUpdating Register the ModelBinder Demo

58. Veryunlikelytowriteyourown

59. ControllerFactory

60. Controller Factory WHAT: Responsible for creating Controllers DEFAULT: Create aninstance of the Controller via Reflectionbased on itsname WHY: Changeifyouwantto create the controller in otherways or ifyouwanttoadd some funtionalities Most of themainIoC container have a customControllerFactory

61. Controller Factory ImplementIControllerFactory CreateController ReleaseController OverrideDefaultControllerFactory GetControllerInstance(TypecontrollerType) Demo

62. ActionInvoker

63. ActionInvoker WHAT: Invokes an action, based only on its name DEFAULT: Call the actionmethod, via reflection, based on itsname, gatheringfilters via attributes and callingthembefore and after WHY: Changeifyouwanttochange the way methods are called, or wantdifferent way toconfigureFilters

64. ActionInvoker Implement IActionInvoker InvokeAction OverrideControllerActionInvoker InvokeActionMethodWithFilters InvokeActionResultWithFilters GetFilters … Demo

65. ViewEngine

66. ViewEngine WHAT: The service that transforms in HTML the data for the user DEFAULT: WebFormviewengine WHY: Changeifyou don’t like the WebFormapproach

67. ViewEngine IViewEngine: UsuallyoverrideVirtualPathProviderViewEngine CreateView IView: Render Demo

68. ModelValidatorProvider

69. ModelValidatorProvider WHAT: Retrieves the validation rules DEFAULT: Validationrules are definedwithDataAnnotationattributes WHY: Changeifyouwanttospecifyvalidationrules in otherways (XML, Database, etc…)

70. ModelValidatorProvider OverridefromModelValidatorProvider ImplementGetValidators

71. ModelMetadataProvider

72. ModelMetadataProvider WHAT: Retrieves the metadataneededfor the templatedhelpers DEFAULT: Metadata are definedwithDataAnnotationattributes WHY: Changeifyouwanttospecifymetadata in otherways (XML, Database, etc…)

73. ModelMetadataProvider InheritfromModelMetadataProvider Implement GetMetadataForType GetMetadataForProperty GetMetadataForProperties

74. Contacts – Simone Chiaretta MSN: simone_ch@hotmail.com Blog: English: http://codeclimber.net.nz/ Italian: http://blogs.ugidotnet.org/piyo/ Twitter: @simonech 73

75. Rating If you liked this talk, please consider rating it: http://speakerrate.com/talks/3669-asp-net-mvc-extensibility 74 Disclaimer:"The viewsexpressed are purelythose of the speaker and may not in anycircumstancesberegarded as stating an official position of the Council"