What are the benefits of Visualforce?
Visual force understands Sales force metadata and
provides access to the respective user interface elements
For
example , it automatically recreate the standard Sales force look and feel
It
conforms to the Model-View-Controller development pattern
What are Visualforce Pages?
• Composed
of HTML , Page tabs and merge fields
• Ability
to reference any CSS , Flex , Flash , AJAX or other Web technology
• Supports
standard query strings for parameters , referenced via /apex/pageName URL
Syntax
• Composed
on the server , not the client
• As
they are created in Apex , they have full access to Apex functionality ( API ,
Web Services etc
• Pages
interact with controllers through components that call data or actions
• Can
be used to maintain state across page interactions ( in wizards , for example )
What are Visualforce Standard Controllers?
Standard Controller
• Are
Available for all API entities / objects , such as Account , Contact
Opportunity etc as well as custom object
• Provide
access to standard Sales force data and behaviour
• Standard
object record data
• Standard
actions like save , edit , delete
• Are
referenced by using :
<apex:pagestandardController = ”Contact” >
What are Expressions and Data Binding?
Visualforce uses the expression syntax ( also
found in merge fields , formulas , and s-controls ) to bind components to Sales
force data and actions in the page’s controller
• All
content in { ! …. } will be evaluated as
an expression.
• {!$User.FirstName}
shows the current user’s first name in a page
• Data
context is provided to controllers by the ID parameter , just as in standard
pages
• Visualforce
pages and components are versioned
• Previous
versions of Visualforce elements remain available after new implementations are
introduced , ensuring that your code works with each release
• The
Version settings tab displays the version of each page or component
Describe Visualforce Namespaces?
Standard tags begin with the word apex
Custom tags begin with the letter c
Application developers can register custom
namespaces to be displayed with custom tags instead of the letter c
What are the different ways of Incorporating
Visualforce Pages?
Visualforce pages can be incorporated into your
Sales force UI by :-
• Creating
Links to reference the unique page URL
• Overriding
standard buttons to route to the new page
• Creating
custom tabs for the new page
• Creating
custom tabs and links to route to the new page
• Embedding
pages into page layouts ( similar to inline s-controls )
• Adding
Pages to a dashboard
• Using
pages as custom help for a custom object
What are Force. com Sites?
• Public
, unauthenticated Web sites
• Accessed
from branded domain names
• Built
with Visualforce pages
• From
data and content in a Sales force application
What are Tag Basics?
Visualforce includes a tag library similar to
HTML and XML mark-up language
You can include text directly into the
Visualforce page
You can use HTML tags within a Visualforcepage ,
including
HTML comment tags
Formatting tags
You can use JavaScript within a Visualforce page
as well , but you will often find it easier to use equivalent Visualforce tags
• Note:-
You cannot use JavaScript line commenting except within <script> tags
Visualforce components ( tags ) all begin with
the apex : prefix
All pages must be enclosed by a set of
<apex:page> tags
Tags may contain attributes that have values (
in quotes ) to help further define them
• Attribute
values are typed to be strings , collections , ids etc
Like XML ,Visualforce must be well-formed. At a high level this means
• Every
Visualforce start tag <tagName> must have a matching end tag < /
tagName> or be a self contained tag <tagName / >
• Tags
are hierarchical and must be closed in the reverse order they were opened
What are Tag Bindings? How many types of Tag
Bindings are there?
Bindings are ways to relate Visualforce
components with either the page controller or other page components
There are primarily three types of bindings for
Visualforce components
• Data bindings : using the expression syntax to pull in data from the data set made
available by the page controller
• Action bindings : using the expression syntax to call action methods for functions
coded in the page controller
• Component bindings : using component attribute values to reference other component IDs
• These
other components must have set a value for the id attribute
Data Binding works because the page can access
the data made available through the controller
In a similar manner , actions that are available
through the controller can be called using the same expression syntax. These
can be :-
• Standard
actions , such as save and edit
• Custom
actions that provide custom functionality
Describe Component Binding via component IDs?
All Visualforce tags have an optional id
attribute that can be used to refer to the
tag component
• This
id is used as the document model access ( DOM ) ID when the page is rendered
• The
tag can be referenced by the id by other tags , JavaScript , or other
Web-enabled languages
Sales force recommends using unique ids within
each page
• If
not unique , you may need to specify the hierarchy of ids to locate the correct
component
• The
hierarchy prevents the possibility of duplicate IDs on HTML elements generated
by components
• However
, raw HTML could produce dupes
What is the purpose of <apex:pageBlock>
tag?
This tag creates an area of a page that is
similar to a detail page but with no default content
Attributes include :-
• Mode(String):
either detail or edit mode. Edit mode
does not show field lines. (detail)
• Title(String):
title displayed on the page block.
• tabStyle(String):
Sales force object used to copy the color and style for this page block.
The pageBlock tags can include facet tags ,
which are child tags that are often used to add or override headers and footers
to areas or tables
What are Tab Styles?
You can specify the tab style at the <apex:page>or <apex:pageBlock>levels of
Visualforce pages
• Remember
that tab styles refer to the icon and color used on the tab
In standard controllers , the page automatically
takes on the style of the associate object
In Custom controllers , if you choose not to
specify a tab style the page automatically takes on the style of the Home Tab
What is the purpose of
<apex:sectionHeader> tag?
This tag creates the standard colored header bar
displayed under the tabs in the Sales force UI
Attributes include
• Title(Stirng):
the text displayed at the top of the bar.
• Subtitle(string):
the text displayed under the title.
• Help(String):
the URL for the page’s help file. The
link appears on the right.
This tag creates a set of buttons that are
styled like standard Sales force buttons
• The
individual buttons are created using the commandButton tag
Attributes include
• Location(String):
either top, bottom, or both. (both)
This tag must be used within a PageBlockSection
component to create a pair of cells as an item in a column , instead of using
inputField or other tags that automatically create name / value data pairs
Each column has two cells ; one for the label
and one for the value
These can be added with outputLabel tags and
inputText or other UI widget components
What are the tags that can be used for Page
Inclusions?
There are three tags that allow you to insert
other web content within an iframe
Iframe : insert web content using a URL
s-control : insert an s-control ( similar to an
inline s-control )
include : insert another Visualforce page
What are Template tags?
These are a series of tags that are used to
create Visualforce template pages that can help define reusable components for
baseline pages
What is the purpose of <apex:relatedList/>
tag?
This single tag creates just the related list
for records related to the parent
record
Attributes include:-
• List
( String ) : the name of the child relationship from which to return the
records
• Subject
( String ) : the id of the record that should provide the data for the related
list
• pageSize(
Integer ) : the number of records to display by default(5)
No comments:
Post a Comment