1.2 KiB
1.2 KiB
Dynamic Default Values
The [api:DataObject::$defaults] array allows you to specify simple static values to be the default value for when a record is created, but in many situations default values needs to be dynamically calculated. In order to do this, the [api:DataObjectSet->populateDefaults()] method will need to be overloaded.
This method is called whenever a new record is instantiated, and you must be sure to call the method on the parent object!
A simple example is to set a field to the current date and time:
:::php
/**
* Sets the Date field to the current date.
*/
public function populateDefaults() {
$this->Date = date('Y-m-d');
parent::populateDefaults();
}
It's also possible to get the data from any other source, or another object, just by using the usual data retrieval methods. For example:
:::php
/**
* This method combines the Title of the parent object with the Title of this
* object in the FullTitle field.
*/
public function populateDefaults() {
if($parent = $this->Parent()) {
$this->FullTitle = $parent->Title . ': ' . $this->Title;
} else {
$this->FullTitle = $this->Title;
}
parent::populateDefaults();
}