What is extensions in VF page?

What is extensions in VF page?

Use custom controllers when you want your Visualforce page to run entirely in system mode, which does not enforce the permissions and field-level security of the current user. A controller extension is an Apex class that extends the functionality of a standard or custom controller.

What is the use of ApexPages StandardController?

StandardController objects reference the pre-built Visualforce controllers provided by Salesforce. The only time it is necessary to refer to a StandardController object is when defining an extension for a standard controller. StandardController is the data type of the single argument in the extension class constructor.

Which is an example of a controller extension?

A controller extension is any Apex class containing a constructor that takes a single argument of type ApexPages.StandardController or CustomControllerName, where CustomControllerName is the name of a custom controller you want to extend. The following class is a simple example of a controller extension:

What happens when you extend a standard controller?

If the Controller Extension extends a Standard Controller it will execute in user mode in which permissions, field-level security, and sharing rules of the current user apply, even though a controller extension class executes in system mode. Standard controllers: It is used for performing operations on a single record.

How is a standardcontroller used in a constructor?

The following example shows how a StandardController object can be used in the constructor for a standard controller extension: // controller. The following Visualforce markup shows how the controller extension from above can be used in a page:

When to use a controller extension in apex?

Controller Extension is an Apex Code that extends the functionality of a Standard or Custom Controller. When we want to use the built-in functionality of a Standard Controller but override one or more actions, like edit, view, save, or delete.