1. Anatomy of an ASP.NET Page

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

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

4. (Review) 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. ASP.NET Manual Event Wiring
We will use AutoEventWireUp so this step will be unnecessary

6. 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

7. Compiling an ASP page (Illustration)

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

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

10. Processing Directives (Example)
Processing directives have the following format:
directive_name attribute=“value” attribute=“value” %>
Processing directives and asp expressions work similarly

11. 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

12. 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

13. 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
This name corresponds to the name of the class declared in the underlying .cs file.

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

15. 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)

16. 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”

17. Page Life Cycle (1)
When a page is requested or posted back, the runtime figures out why the page is being processed
Normal request (First time visiting a page)
Postback (Page posts back to the same page)
Cross-page postback (Page posts back to another page)
Callback (We postback part of a page and return dat)

18. Page Lifecycle (Illustration)

19. Dissection Page methods can be overridden
Page events are events that you can handle as the page is loaded and processed
Control methods and events work similar to page methods and events. We handle these as controls are initialized

20. 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

21. Page Life Cycle (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

22. Page Life Cycle (InitComplete Event)
Here, view state tracking is turn on
The event fires only for the page

23. 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

24. 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

25. 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

26. 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

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

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

29. 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

30. 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

31. 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

32. 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

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

34. 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

35. 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

36. 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