Development with the Force.com Platform: Building Business Applications in the Cloud, Third Edition

Custom Controllers

Custom controllers provide complete control over the behavior of a page with no default implementation. A custom controller is simply an Apex class designed to be bound to a Visualforce page. There is no new syntax to learn. At a high level, building a custom controller consists of defining the data to make available to the page and the actions that the page can invoke.

Exposing Data

The purpose of exposing data in a controller is to make it available to the page. Within a page, page components can use expressions to bind to it and render HTML or some other representation of the data. This binding is by reference, so data modified in the page can also be modified in the controller.

Simply making a variable public does not ...