在codeigniter drop_down中设置选项

i'm loading my dropdown with this and trying set an option:

<div class="form-group">
                <label for="areas" class="col-lg-2 control-label">Áreas</label>
                    <div class="col-lg-3">
                        <select class="form-control" id="areasCadastradas" name="areas">
                         <?php 

                            foreach($areas as $row)
                            { 
                              echo '<option  value="'.$row->id.'">'.$row->descricao.'</option>';

                            }

                         ?>
                        </select>
                        <?php echo $record->id_area;
                            echo set_select('areas', $record->id_area); ?>
                  </div>
             </div>

it is not working... i need load the dropdown and set an option.

edit: the loading it is working.. but i cant set the option

edit 2:

foreach($areas as $row)
{ 
echo '<option  value="'.$row->id.' '.set_select('areas', $record->id, False);.'">'.$row->descricao.'</option>';
}

This code may helps you

$options = array();
                        foreach ($areas as $row)
                        {
                             $options[$row->id]=$row->descricao;

                        }
                        echo form_dropdown('areas', $options, $record->id);

And,i hopes you already loaded form_validation library files in your controller

$this->load->library('form_validation');

solution:

<select class="form-control" id="comarcasCadastradas" name="comarcas">
                         <?php 

                            foreach($comarcas as $row)
                            { 
                              if ($record->id_comarca == $row->id) {
                                    echo '<option  value="'.$row->id.'" selected>'.$row->nome.'</option>';
                                } else {
                                    echo '<option  value="'.$row->id.'">'.$row->nome.'</option>';
                                }
                            }
                         ?>

I suggest using CI's Form Helper

<?php
// All the code in the <?php tags should be in the controller and then vars passed to the view.
// Putting it all in the view here for the sake of a simple answer.

$this->load->helper('form');

$options = []; //empty array to start
foreach($areas as $row)
{
    $options[$row->id] = $row->descricao;
}
$dropdown_data = [
  'name' => 'areas',
  'options' => $options,
  'selected' => $record->id_area,
  'class' => "form-control",
  'id' => "areasCadastradas"
];
?>

<div class="form-group">
    <label for="areas" class="col-lg-2 control-label">Áreas</label>
    <div class="col-lg-3">
        <?php
        echo form_dropdown($dropdown_data);
        ?>
    </div>
</div>

I assume that $record->id_area is an array appropriate for your dropdown.