Load views after posting a form!

[eluser]Unknown[/eluser]
Hello everyone!

I'm new to the codeigniter framework and I'm impressed of how fast you can write code with it! The only problem I have is the following and I hope there is a good way to solve it!

I will keep it simple so let's say I have 2 controllers (login.php & site.php) and 1 view (home.php).

site.php

Code:

<?php

class Site extends Controller {

    function index()
    {
        $data['a'] = 'example';
        $data['b'] = 'test';

        $this->load->view('home.php', $data);
    }

}

login.php

Code:

<?php

class Login extends Controller {

    function index()
    {
        // Run form validation and if ok do the following
        redirect('site');
        //else
        $data['a'] = 'example';
        $data['b'] = 'test';

        $this->load->view('site', $data);
    }

}

home.php

Code:

html code + form that posts to login.php

My problem is that because the form posts the data to the login.php controller, (if the validation fails and I want to show the errors) I have to load the view again and enter the array $data again because it is essential to the view.

In this case it's ok because this is a small array. But what if I have a view which requires a lot of data (and some of them is from a database!). I have to recreated the data every time I want to load a view from a different controller? Is there a way to load the view by calling the site/index and keep intact the form validation messages?

Thanks in advance.. I hope there is an easy solution to this!