Use dropdown in views exposed filter on text fields with node->title?
I solved the problem, here the code:

&lt;?php

function views_dropdown_form_views_exposed_form_alter(&amp;$form, &amp;$form_state) {
global $user;

// Only alter forms with the necessary field
if (isset($form['title'])) {

// Build a query to get all node ids having the specified field
$query = new EntityFieldQuery();

$results = $query-&gt;entityCondition('entity_type', 'node')
                  -&gt;entityCondition('bundle', 'rapporto_di_lavoro')
                  -&gt;propertyCondition('uid', $user-&gt;uid)
                  -&gt;propertyCondition('title', 'NULL', '!=')
                  -&gt;execute();


// Attach the field values to the nodes
$ids = array_keys($results['node']);
// Add a default so the filter is optional
$options = array('' =&gt; '&lt;select&gt;');

// // Buld the options array based on the query results, overwriting duplicate entries
$query = db_select('node', 'n')
            -&gt;fields('n', array('title'))     
            -&gt;condition('n.nid', $ids, 'IN');

$results = $query-&gt;execute()-&gt;fetchAll();

foreach($results as $id =&gt; $node) {
  $value = $node-&gt;title;
  $options[$value] = $value;
}


// // Alter the field
$form['title']['#type'] = 'select';
$form['title']['#options'] = $options;
$form['title']['#size'] = 1;
}}




I hope could help someone :)