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.

Setting Read-Only Mode for Controller Methods

Visualforce controller methods can, with some important limitations, use the Apex ReadOnly annotation, even if the page itself isn’t in read-only mode.
Visualforce controller methods with the @ReadOnly annotation automatically take advantage of read-only mode.. However, restrictions on the @ReadOnly annotation means that, for Visualforce controller methods, a read-only method must also have the @RemoteAction annotation. The @RemoteAction annotation requires that the method be:
  • Either global or public
  • static

Enabling read-only mode. by using the @ReadOnly annotation must be done on the top level method call. If the top level method call doesn’t have the@ReadOnly annotation, the normal restrictions on maximum queried rows are enforced for the entire request, even if secondary methods are annotated with @ReadOnly.

Using the @ReadOnly annotation on a controller method allows you to retrieve a larger collection of records as the result of a Visualforce expression. However, it doesn’t increase the maximum number of items in a collection for iteration components. If you want to iterate over larger collections of results, you need to enable read-only mode. for the entire page.