Visualforce Developer Guide

Introducing Visualforce
Tools for Visualforce Development
Getting a Quick Start with Visualforce
Customizing the Appearance and Output of Visualforce Pages
Standard Controllers
Standard List Controllers
Custom Controllers and Controller Extensions
What are Custom Controllers and Controller Extensions?
Build a Custom Controller
Building a Controller Extension
Building a Custom List Controller
Controller Methods
Controller Class Security
Working with Large Sets of Data
Setting Read-Only Mode for an Entire Page
Setting Read-Only Mode for Controller Methods
Considerations for Creating Custom Controllers and Controller Extensions
Order of Execution in a Visualforce Page
Test a Custom Controller
Validation Rules and Custom Controllers
Using the transient Keyword
Advanced Examples
Override Buttons, Links, and Tabs with Visualforce
Using Static Resources
Creating and Using Custom Components
Dynamic Visualforce Bindings
Dynamic Visualforce Components
Integrate Email with Visualforce
Visualforce Charting
Creating Maps with Visualforce
Render Flows with Visualforce
Templating with Visualforce
Developing Salesforce Apps with Visualforce
Adding Visualforce to a Salesforce AppExchange App
Using JavaScript in Visualforce Pages
Communicating Across the DOM with Lightning Message Service
Visualforce Best Practices
Standard Visualforce Component Reference
Appendices
PDF

Note: This release is in preview. Features described here don’t become generally available until the latest general availability date that Salesforce announces for this release. Before then, and where features are noted as beta, pilot, or developer preview, we can’t guarantee general availability within any particular time frame or at all. Make your purchase decisions only on the basis of generally available products and features.

Working with Large Sets of Data

Visualforce custom controllers and controller extensions are subject to Apex governor limits. For more information about governor limits. Additionally, Visualforce iteration components, such as <apex:pageBlockTable> and <apex:repeat>, are limited to a maximum of 1,000 items in the collection they iterate over.

Sometimes your Visualforce pages may need to work with or display larger sets of data, but not need to make modifications to that data; for example, if you are providing custom reporting and analytics. Visualforce offers developers a “read-only mode”, which relaxes the limit on the number of rows which can be queried in one request, and increases the limit on the number of collection items which can be iterated over within the page.

You can specify read-only mode either for an entire page or, with certain limitations, on individual components or methods.

You can only iterate over large sets of data if you specify read-only mode for the entire page.

Note