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