Form validation problem with CodeIgniter - forms

Question

I have this view:
<?php echo form_open(); ?>
<?php echo form_input('username', '', ''); ?>
<?php echo form_submit('submit', 'Submit'); ?>
<?php echo form_close(); ?>
<?php echo validation_errors(); ?>
and this controller method:
function test() {
$username = $this->input->post('username');
$this->form_validation->set_rules($username, 'Username', 'required|min_length[4]');
if ($this->form_validation->run() !== FALSE) {
echo 'Tada!';
}
$this->load->view('test');
}
but when I leave the username field blank, nothing happens. However, if I type in something in it will tell me the field is required. I've downloaded and given CI a fresh install almost ten times now, trying to load with and without different helpers etc. It's becoming really frustrating, please help.

Answer 1

Try using this:
$this->form_validation->set_rules('username', 'Username', 'required|min_length[4]');

Answer 2

The problem lies in the first parameter of set_rules, which is the field name.
The $username you're passing is basically setting the field name to validate as whatever the user puts in the input field. If you were to type 'username' into the input box, you'd see that your form validates.
Change the line
$this->form_validation->set_rules($username, 'Username', 'required|min_length[4]');
to
$this->form_validation->set_rules('username', 'Username', 'required|min_length[4]');

Answer 3

Maybe is the problem of this line
<?php echo form_open(); ?>
If you leave it blank it basically send back to the controller itself and calling the construct and index function only. In this case your function dealing with form processing is "test()"
try this
<?php echo form_open('yourControllerName/test'); ?> //test is the function dealing with
if it is not working try on this
<?php echo form_open('test'); ?>