1. Anatomy of an ASP.NET Page

2. Slide 2 My Version of the Big Picture (1) ASP Worker (Engine) Your application Runs Server Other applications User 1User 2 Session 1Session 2 Client (Browser) Request Response

3. Slide 3 My Version of the Big Picture (2) Your ASP.NET application Server Web.config HTML Docs Master Page(s) User Controls contains Content Page(s) ASP Pages Site.master

4. Slide 4 What is an ASP.NET Page? Roughly speaking, an ASP.NET page contains Markup (appears in the.aspx page) Server-side code that the ASP.NET worker executes (appears in the.aspx page or in a separate code behind page) The resulting HTML is sent out to the client (browser) by the asp worker process

5. Slide 5 ASP.NET Coding There are two ways to do it Inline (code appears in the same file as the.aspx file) Put in a block with runat=“server” Separate code behind file This is what I generally do

6. Slide 6 ASP.NET Inline Code

7. Slide 7 ASP.NET Code Behind They are matching.aspx and.aspx.cs files that are hopelessly tied together @Page directives are important The CodeBehind attribute points to the.cs file The Language attribute identifies the programming language VB / C#

8. Slide 8 ASP.NET Code Behind

9. Slide 9 Compiling an ASP.NET Page An ASP.NET page is compiled when it is rendered for the first time A page is compiled to a class that derives from System.Web.UI.Page Parse the.aspx file and create a class that derives from Page The preceding class is then compiled to an assembly This process is transparent and is handled by ASP.NET itself

10. Slide 10 Compiling an ASP page (Illustration)

11. Slide 11 IIS File Mappings.asax –application files.ascx – ASP user controls.asmx – Web services.aspx – ASP.NET Web pages

12. Slide 12 IIS Process Models Hosting prior to Windows Server 2003 uses IIS 5.0 Later versions use IIS 6.0 or IIS 7.0 In this class, we will assume and use the IIS 7.0 process model but for the most part it will not matter

13. Slide 13 Processing Directives (1) Processing directives are used to configure the runtime environment Directives can appear anywhere on a page but best practices dictate that they appear at the beginning of the page Directives begin with Make sure you don’t forget the %>

14. Slide 14 Processing Directives (2) Processing directive are used to configure the runtime environment Processing directives have the following format:

15. Slide 15 Processing Directives (3) Processing directives are used to Describe the page itself ( @ Page ) Describe a special type of a page called a master page ( @ Master ) Control caching ( @ OutputCache ) And more We’ll refer back to these as the course progresses

16. Slide 16 Processing Directives ( @ Page ) It can appear only in.aspx pages Attributes are divided into roughly three categories Compilation Page behavior Page output There are other tools to configure the same options beyond processing directives

17. Slide 17 Processing Directives Page Compilation CodeFile lists the file containing the VB or C# code for the.aspx page Language describes the programming language for the CodeFile ClassName explicitly sets the name of the class created upon compilation

18. Slide 18 Processing Directives (Page Output) Most of these directives relate to localization and multiple cultures ClientTarget allows pages to be rendered for a specific browser

19. Slide 19 Introduction to the Page Class The Page class provides the basic behavior for an ASP Web page It’s objects allow you to reference The application itself ( Application ) The server itself ( Server ) The HTTP request ( HttpRequest ) The HTTP response ( HttpResponse ) The user’s session ( Session )

20. Slide 20 Introduction to Page Events First, this topic is very important to getting your ASP applications to work ASP uses the eventing model to Persist state from one postback to the next Create static and dynamic controls Bind control instances to data sources And much more As your book says “state is an illusion of continuity”

21. Slide 21 Page Life Cycle (1) When a page is requested The runtime figures out why the page is being processed Normal request Postback Cross-page postback callback

22. Slide 22 Page Life Cycle ( PreInit Event) It’s the first event in the page life cycle Master page has not been associated Themes have not been associated It’s possible to change master page or theme association at this time IsCallback, IsCrossPagePostback and IsPostBack are set at this time Control instances have been created so you CAN reference them in code

23. Slide 23 Page Life Cycle ( Init Event) Init Event Master page and theme have been set and cannot be changed Child controls are initialized and the ID is set Child controls are initialized recursively Init event fires for all child controls before the event fires for the page itself Note that view state has not been restored yet

24. Slide 24 Page Life Cycle ( InitComplete Event) Here, view state tracking is turn on The event fires only for the page PreLoad event System initialization is complete We don’t typically do much here The event only fires for pages and not controls

25. Slide 25 Page Life Cycle ( PreLoad Event) System initialization is complete We don’t typically do much here The event only fires for pages and not controls

26. Slide 26 Page Life Cycle ( Load Event) The event is raised first for the page and then recursively for all child controls You can access control properties and view state at this time Create dynamic controls in this event We won’t work with dynamic controls here Use IsPostBack to check whether the page is being loaded in response to a postback or new page

27. Slide 27 Page Life Cycle ( LoadComplete Event) LoadComplete fires after Load At this point, the page begins its rendering phase We don’t generally do much here

28. Slide 28 Page Life Cycle ( PreRender Event) Fires for the page first and then recursively for all controls Use to update controls before the output is rendered PreRenderComplete event Raised only for the page after PreRender has fired for all child control instances

29. Slide 29 Page Life Cycle ( PreRenderComplete Event) Raised only for the page after PreRender has fired for all child control instances

30. Slide 30 Page Life Cycle ( SaveStateComplete Event) It fires for all constituent controls and then the page itself Any changes made will not be persisted after this Next, the markup is generated

31. Slide 31 Page Life Cycle ( Unload Event) After rendering, the event fires for all control instances and then the page itself Use this event to close files or database connections

32. Slide 32 Page Class Properties (1) Controls returns a collection of controls on the page IsPostBack indicates whether the page is being loaded in response to a postback or is being loaded for the first time PreviousPage returns a reference to the caller page Only meaningful in case of a cross-page postback Check IsCrossPagePostback

33. Slide 33 Page Class Properties (2) ClientTarget allows you to specify the type of browser Note that automatic browser detection is disabled EnableTheming and Theme allows you to set page themes (more later) MaintainScrollPositionOnPostback allows the page position to be persisted from one postback to the next

34. Slide 34 Page Class Methods (1) DataBind binds all data bound controls to their data sources (more later) Validate causes validation controls to validate their data SetFocus sets input focus to the desired control instance There are methods to work with client script (discussed in Chapter 5)

35. Slide 35 Folder Structure So far, you have seen a project from an empty template Now for a real one

36. Slide 36 Folder Structure You get many template files and folders for free All this gets compiled on the server to make up an ASP.NET app

37. Slide 37 Folder Structure App_Code is designed to store shared code files (classes,.wsdl pages) App_Data is designed to store data files Users can read and write data in this folder The folder Scripts is not magical but we store JavaScript and jQuery here Note that the jQuery scripts are copied here by default from the standard template

38. Slide 38 Global.asax Global.asax is the global application startup, shutdown, and error file It contains procedures that are called by the application infrastructure Application_Start called when the application gets its first request Application_End not used much Application_error to handle all unhandled errors

39. Slide 39 The Class Designer This is not really and ASP thing as it is a.NET thing It lets you build the prototypes for the various class parts