Pass a variable from one page to another in CodeIgniter

Question

In codeigniter, on the page /categories I have a table with the rows of all category items. There is a <select> box to filter the categories by components:

<form accept-charset="utf-8" method="post" action="/categories/get_categories">
    <select onchange="this.form.submit()" name="selectCatsByComponent">
        <option value="0" selected="selected">-- Choose a component --</option>
        <option value="1">Content</option>
        <option value="2">E-commerce</option>
    </select>
</form>

So whenever i select an <option> from the <select> list , and I click on the button ADD NEW CATEGORY, i want to pass that POST value into the next page and automatically select the corresponding component id in the same <select> list.

I tried this but it seems not working:

    if( $this->input->post('selectCatsByComponent') )
        $com_id = $this->input->post('selectCatsByComponent');

Any tips ?

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Answer 1

I guess the options have to use a check when the select is written.

<?php
/* Use a default, and try to get the value of the previous selection. */
$com_id = 0;
if( $this->input->post('selectCatsByComponent') )
    $com_id = $this->input->post('selectCatsByComponent');

$catsByComponentOptions = Array('-- Choose a component --','Content', 'E-commerce');
?>

/* start the form */
<form accept-charset="utf-8" method="post" action="/categories/get_categories">
    <select onchange="this.form.submit()" name="selectCatsByComponent">

<?php 
/* write out each option, checking to see if it needs to be selected. */
foreach ($catsByComponentOptions as $key => $value){
    echo '<option value="'. $key .'" ';
    if ($key === '$com_id')
        echo ' selected="selected" '; 
    echo ">$value</option>";
}
?>

</form>