how to remove "with_empty" checkbox for all generated formFilters in symfony 1.4

Configuration.class.php

<?php

class xxxConfiguration extends sfXxxConfiguration
{
    public function setup()
    {
 
        $this->dispatcher->connect('command.filter_options', array($this, 'filterCommandOptions'));
    }
 
    /**
     * Filters command options.
     *
     * @param   sfEvent $event
     * @param   array   $options
     *
     * @return  array
     */
    public function filterCommandOptions(sfEvent $event, $options) {

        // force generator class when running build-filters task
        if ('sfDoctrineBuildFiltersTask' === get_class($event->getSubject()))
        {
          $options = array('--generator-class=myFormFilterGenerator');
        }
        return $options;
    }
}

myFormFilterGenerator.class.php

<?php

/**
 * @author johnwards
 * @link http://stackoverflow.com/questions/2881379/symfony-forms-how-to-change-default-widget-for-form-generation
 */
class myFormFilterGenerator extends sfDoctrineFormFilterGenerator
{

  public function getWidgetOptionsForColumn($column)
  {
    switch ($column->getDoctrineType())
    {
      case 'string';
        return "array('with_empty'=> false)";
        break;
      default:
        return parent::getWidgetOptionsForColumn($column);
    }
  }
  
}

Hello,

I tried your code
put the dispatcher code in config/ProjectConfiguration.class.php
and myFormFilterGenerator .class.php in lib folder.
When I ran the task: doctrine:build-filters i have this message:
The execution of task "doctrine:build-filters" failed.

• Not enough arguments.

symfony doctrine:build-filters [--application[="..."]] [--env="..."] [--model-dir-name="..."] [--filter-dir-name="..."] [--generator-class="..."]

What's going wrong?
Thks