preGet not working

I want to change the field value of pregroupdata.status before datatable read from database. I use preGet event to implement. But it is not work.

There is my code.

<?php
header("Conten-Type:text/html;charset=utf-8");
/*
 * Example PHP implementation used for the index.html example
 */

// DataTables PHP library
include( "../../php/DataTables.php" );

// Alias Editor classes so they are easy to use
use
    DataTables\Editor,
    DataTables\Editor\Field,
    DataTables\Editor\Format,
    DataTables\Editor\Mjoin,
    DataTables\Editor\Options,
    DataTables\Editor\Upload,
    DataTables\Editor\Validate;

// Build our Editor instance and process the data coming from _POST
Editor::inst( $db, 'pregroupdata' )
    ->fields(
        Field::inst( 'pregroupdata.appdate' ),
        Field::inst( 'pregroupdata.status' )->set(Field::SET_BOTH),
        Field::inst( 'pregroupdata.setupdate' ),
        Field::inst( 'pregroupdata.pastoralid' )->validator ( 'Validate::notEmpty' )
                                   ->options ( Options::inst()
                                                ->table( 'pastoral' )
                                                ->value( 'id' )
                                                ->label( 'name' )
                                             ),
        Field::inst( 'pname.name' ),
        Field::inst( 'pregroupdata.zoneid' )->validator ( 'Validate::notEmpty' )
                               ->options ( Options::inst()
                                                ->table( 'zonedata' )
                                                ->value( 'id' )
                                                ->label( 'name' )
                                             ),
        Field::inst( 'zname.name' ),
        Field::inst( 'pregroupdata.leaderid' )->validator ( 'Validate::notEmpty' )
                                 ->options ( Options::inst()
                                                ->table( 'leader' )
                                                ->value( 'id' )
                                                ->label( 'name' )
                                             ),
        Field::inst( 'lname.name' ),
        Field::inst( 'lname.phone' ),
        Field::inst( 'lname.cellphone' ),
        Field::inst( 'lname.identity' ),
        Field::inst( 'pregroupdata.groupname' ),
        Field::inst( 'pregroupdata.gdate' ),
        Field::inst( 'pregroupdata.gtime' ),
        Field::inst( 'pregroupdata.gplace' ),
        Field::inst( 'pregroupdata.property' ),
        Field::inst( 'zlname.name'),
        Field::inst( 'zlname.phone'),
        Field::inst( 'zlname.cellphone'),
        Field::inst( 'zlname.identity' )
    )
    ->leftJoin('leader as lname', 'pregroupdata.leaderid','=','lname.id')
    ->leftJoin('zonedata as zname', 'pregroupdata.zoneid','=','zname.id')
    ->leftJoin('pastoral as pname', 'pregroupdata.pastoralid','=','pname.id')
    ->leftJoin('leader as zlname', 'zlname.id','=','zname.leaderid')
    ->on('preGet', function($editor, $id){
        $editor
            ->field('pregroupdata.status')
            ->setValue('test');
    })
    ->process( $_POST )
    ->json();

Edited by Allan - Syntax highlighting. Details on how to highlight code using markdown can be found in this guide.