Codeigniter下拉菜单不起作用

Question

In the below codeigniter code i have placed controller ,model and view .In my login i have create username ,password and college in dropdown for validate the user.But i got error in college_name drop down Message: Undefined variable: validate,Message: Invalid argument supplied for foreach().Pls help me to solve the issue. Controller

function college()
{
    $this->load->helper('url');
    $data = array();

    $this->load->model("membership_model");
    $data['validate']  = $this->Membership_model->validate();


    $this->load->view('login_form');


}
function validate_credentials()
    {       
        $this->load->model('membership_model');
        $query = $this->membership_model->validate();

        if($query) // if the user's credentials validated...
        {
            $data = array(
                'username' => $this->input->post('username'),
                'is_logged_in' => true
            );
            if($query->num_rows()>0){
             $status = $query->row()->account_status;}
            else {
             $status = ''; }
             //Account active
            if($status == 'active')
            {
               $this->session->set_userdata($data);
               redirect('site1/members_area');
            }
            else  if ($status == 'inactive')//Account In active
            {  $this->inactive();
              }
              else // incorrect username or password
        {
            $this->invalid();
        }
        }

    }   

model:

function validate()
    {
        $this->db->where('username', $this->input->post('username'));
        $this->db->where('password', md5($this->input->post('password')));
        $this->db->where('college_name', $this->input->post('college_name'));
          $query = $this->db->query("SELECT college_name FROM membership ");
        $query = $this->db->get('membership');
        return $query->result();
    }

view:

<?php 
    echo form_open('login/validate_credentials');
    echo form_input('username', 'Username');
    echo form_password('password', 'Password');
    $array = array();
           foreach($validate as $row ){
    $array[] = $row->college_name;
}
            echo form_dropdown('validate',  $array);


    echo form_submit('submit', 'Login');
    echo anchor('login/signup', 'Create Account');
    echo form_close();
    ?>

Answer 1

Try to use correct camel case here

$this->Membership_model->validate(); as $this->membership_model->validate();

Also you need to pass the $data variable to view file.

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

EDIT:

In the validate() method you used the same variable ($query) for 2 different queries and return the query result. Make sure you had returned the correct result there.