8. Developers can use Visualforce pages to:
Override standard buttons, such as the New button for
accounts, or the Save button for contacts
Override tab overview pages, such as the Accounts
tab home page
Define custom tabs
Create dashboard components or custom help pages
Customize, extend, or integrate the sidebars in the
Service Cloud console (custom console components)
9. Displaying Field Values with Visualforce
Visualforce pages use the same expression language
as formulas—that is, anything inside {! } is evaluated as
an expression that can access values from records that
are currently in context. For example, you can display
the current user's first name by adding the {!
$User.FirstName} expression
10. Controllers
A Visualforce controller is a set of instructions that
specify what happens when a user interacts with the
components specified in associated Visualforce
markup, such as when a user clicks a button or link.
Controllers also provide access to the data that should
be displayed in a page, and can modify component
behavior.
Types of Controllers :1. Standard Controller
2. Custom Controller
3. Extension
11. Controllers
Visualforce markup can use the following types of
controller extension and custom controller methods:
• Action
• Getter
• Setter
12. Order of Execution in a Visualforce Page
There are two types of Visualforce page requests:
• A get request is an initial request for a page either made
when a user enters an URL or when a link or button is
clicked that takes the user to a new page.
• A postback request is made when user interaction
requires a page update, such as when a user clicks on
a Save button and triggers a save action.
15. Using JavaScript and CSS in Visualforce
Pages
Using JavaScript in Visualforce pages gives you
access to a wide range of existing JavaScript
functionality,
16. Some Tags of VisualForce :1. <apex:page> calls an action when the page is loaded
2. <apex:actionFunction> defines a new JavaScript function that
calls an action
3. <apex:stylesheet value="{!$Resource.<filename>}"/>
4. <apex:outputText>
5. <apex:commandButton> creates a button that calls an action
6. <apex:commandLink> creates a link that calls an action
7. <apex:actionSupport> makes an event (such as “onclick”,
“onmouseover”, and so on) on another, named component,
call an action.
17. Some Tags of VisualForce :8. <apex:pageBlock >
9. <apex:pageBlockTable value="{!accounts}" var="a">
10. <apex:column value="{!a.name}"/>
11. <apex:form id="theForm">
