Visualforce

Question 1

What is Visualforce?

Answer 1

Visualforce is a programmatic user interface framework that is used to build complex interfaces that are native to the Salesforce platform

• has it’s own markup language
• can include HTML w/in Visualforce page
• offers standard components (visualforce component library)
• uses server-side Apex controllers to interact with database

Question 2

How is Visualforce framework able to interact with a database?

Answer 2

• the Visualforce framework makes use of server-side Apex controllers to be able to interact with the database

Question 3

What static resources?

Answer 3

they are files that are uploaded to and stored within our orgs so that we can reference them and use them throughout the platform

Question 4

What is the syntax for referencing static resource?

Answer 4

single file

{!$Resource.resourceName}

archived file

{!URLFOR($Resource.archiveName, ‘fileName’)}

Question 5

What are custom labels?

Answer 5

custom labels can be used in Visualforce, Apex, and in Lightning components

• they allow us to translate a message into the language in the viewing user’s settings, provided that we’ve added support for that language

Question 6

How to reference Custom Labels?

Answer 6

Reference in Apex by using the System.Label class:

System.Label.Custom_Label_API_Name

Reference in Visualforce by using expression syntax and the $Label global variables:

{!$Label.Custom_Label_API_Name}

Question 7

What are the different types of Apex controllers?

Answer 7

• standard controller
• standard set controller (i.e. standard list controller)
• controller extension
• custom controller

Question 8

What is expression syntax?

Answer 8

• expression syntax is used to notify the framework that the value we’re providing is a reference to something else and not meant to be interpreted literally
• syntax: {!referencedValue}
• used w/ action and data binding

Question 9

What is action binding?

Answer 9

• action binding is the act of coupling a method inside a Visualforce page’s Apex controller to an event on the page through the syntax {!methodName}

Question 10

What is data binding?

Answer 10

• data binding is act of coupling a variable in the Apex controller to a value on our Visualforce page through the format {!variableName}

Question 11

What is a Standard Controller?

Answer 11

• a standard controller is a pre-written, Salesforce-made Apex class that provides functionality for our Visualforce pages (similar to lightning data services
• automatically created for custom objects
• same functionality as lightning record pages (save,delete… record)

Question 12

How do you declare a standardController?

Answer 12

• declared by setting standardController attribute in the opening [apex:page] tag, passing the API name of the object that we want to use the standard controller of

[apex:page standardController=”Account”]{!account.Name}[/apex:page]

Question 13

What is a Standard Set Controller

Answer 13

• while standard controllers only allow us to interact with one record at a time, the prebuilt standard set controllers allow us to work with groups of records at a single time
• Visualforce pages that use the standard set controller default to displaying at most 20 records per page
• contains methods for pagination

Question 14

How do you declare Standard Set Controller?

Answer 14

• to declare the use of a standard set controller in a Visualforce page, we’ll set the standardController and recordSetVar attributes in the opening
  
  • standardController takes the API name of the object we’re working with
  • recordSetVar takes a variable name that we’ll use to reference the list of records throughout the remainder of our Visualforce page

Question 15

What is pagination?

Answer 15

• pagination is the act of dividing records into multiple pages so that the user isn’t overwhelmed with a lengthy table

Question 16

How do you declare Standard Set Controller?

Answer 16

• to declare the use of a standard set controller in a Visualforce page, we’ll set the standardController and recordSetVar attributes in the opening
  
  • standardController takes the API name of the object we’re working with
  • recordSetVar takes a variable name that we’ll use to reference the list of records throughout the remainder of our Visualforce page

Question 17

What is Controller Extensions?

Answer 17

• controller extensions are custom Apex classes that provide further functionality to a Visualforce page while still allowing us to make use of a standard controller
• we can also use controller extensions to override functions from a standard or custom controller
  
  • Visualforce evaluates our controller extensions before looking in the standard or custom controller for our page for the action bound method or data bound variable - this behavior is what allows us to override controller methods with controller extensions
• the Apex class serving as our controller extension will have to adhere to a requirement for its constructor that depends on the type of controller that we’re extending
  
  • if we’re extending a standard controller, our controller extension class constructor must take a single parameter of the ApexPages.StandardController type
  • if we’re extending a standard set controller, our controller extension class constructor must take a single parameter of the ApexPages.StandardSetController type
  • if we’re extending a custom controller, our controller extension class constructor must take a single parameter of whatever class is serving as our custom controller

Question 18

How do you declare a Controller Extension?

Answer 18

• to declare the use of a controller extension on a Visualforce page, we’ll populate the extensions attribute in the opening tag with the name of the Apex class serving as that controller extension
• we can include one standard controller, one standard set controller, or one custom controller on a Visualforce page - we can’t use combinations of the three or multiples of any of them
• we don’t have a maximum on the number of controller extensions that we can include in a Visualforce page

Question 19

How do we declare custom controllers?

Answer 19

• we declare the use of a custom controller in our Visualforce page by setting the controller attribute in the opening tag, passing it the name of the Apex class that’s serving as our custom controller

we can create them in Apex class

Question 20

Accepting Input with Standard Input Components

Answer 20

• can accept input using standard input components like apex:input
• every input component must be contained within an apex:form

apex: form
apex: inputField value=”{!account.Name}” /apex:inputField

/apex:form

Question 21

How do you display data?

Answer 21

can display data with standard output components like apex:outputField

Question 22

How do you display records in Visualforce?

Answer 22

• by using standard components apex:pageBlockTable OR apex:dataTable
• pageBlockTable includes Salesforce-like styling whereas dataTable has no default styling

Question 23

How do we support inline editing in Visualforce Tables?

Answer 23

by making use of the apex:inlineEditSupport component

Question 24

How do we support inline editing for individual records?

Answer 24

by including apex:detail component

set the inlineedit attribute to true to support inline editing

Question 25

What are Wrapper Classes?

Answer 25

* wrapper classes are Apex classes that are used to **collect multiple values in a single object** to allow us to **make a custom data type** * we can use wrapper classes to display tables of data in our Visualforce pages that mix lists of records with other properties

Question 26

apex:param

Answer 26

allows us to pass a parameter to its parent

Question 27

How would we dynamically instantiate Visualforce components?

Answer 27

* we can dynamically instantiate Visualforce components by using the apex:dynamicComponent

Question 28

What's the advantage of Dynamic Binding?

Answer 28

to use a dynamic binding so that our expression syntax is evaluated at runtime rather than compile time

Question 29

How does Visualforce support partial page rendering?

Answer 29

* apex:actionSupport allows us to **asynchronously** refresh components within **certain portion** of our page * if we're using an [apex:commandLink] or [apex:commandButton], we can specify the **reRender attribute** of these components to be able to **refresh select portions of our page** whenever these components are clicked

Question 30

What are Visualforce wizards

Answer 30

* Visualforce wizards are sets of pages that guide users through a process **one step at a time**, with a different page for each step * to make a Visualforce wizard, we **create a page for each step** and **use the same custom controller** for each page * we can include **buttons** to take users to the **next** or **previous step** in a process by action binding them to controller methods that return a PageReference

Question 31

What is the View State?

Answer 31

* the view state is a **hidden form field** that's included on our Visualforce pages and describes the state (i.e. size, type, name, and/or value) of components on our page, values referenced in fields on our page, and objects instantiated within standard and custom controller code * the server uses it as a base to then apply changes to in response to the user interaction that occurred

Question 32

Visualforce Best Practices

Answer 32

view state size limit is 170kb so we want to minimize it * writing selective SOQL queries so that our controller's variables are as small as they can be * using the transient keyword as appropriate * transient variables aren't included in view state

Question 33

How to test Visualforce Pages

Answer 33

* to test a Visualforce page, we'll often go through **manual testing** with the page itself to ensure that it looks and functions as we desire * for any **custom Apex code** that we create for the page (whether a controller or controller extension), we'll write appropriate test coverage in an **Apex test class**

Question 34

How to create multiple tabs within our page?

Answer 34

* to create multiple tabs within our page, we'll make use of two standard Visualforce components - and

Question 35

Attributes in apex:page

Answer 35

* to make use of a **standard controller**, we specify the **standardController** attribute in our opening [apex:page] tag, passing it the API name of the object that we want to work with * to make use of a **standard set controller**, we specify the **standardController** and **recordSetVar** attributes in our opening [apex:page], passing the API name of the object that we want to work with and a name for the variable that will hold the collection of records from the standard set controller, respectively * to make use of a **controller extension** or (extensions), we specify the **extensions** attribute in our opening [apex:page], passing the name(s) of the Apex class(es) that we're using * to make use of a **custom controller**, we specify the **controller** attribute in our opening [apex:page], passing the name of the Apex class that we're using we can pass a value of pdf to the renderAs attribute to have our page rendered as a PDF