Display the authors in dropdown menu using wp_dropdown_users – Hook/Filter

One of my client faced issue with Autor drop down which is in Admin section.

Display the authors in dropdown menu using hooks.

While creating the New post there was problem with the Author field. There are hundreds of irrelevant selections (users) and it’s difficult to select the right one.

WordPress is by default showing all the users in author drop down. I don’t want to show the other users in author drop down.

I searched for wp_dropdown_users hook or filter. But I did not found any proper solution.

Following articles are found helpful to me.
http://wordpress.org/support/topic/filter-for-post-quick-edit-author-drop-down
http://codex.wordpress.org/Function_Reference/wp_dropdown_users

Using that code I modified the code and I am able to fix the issue. You can put following code in to functions.php file.

 /*
 * Hook for showing Admin and Author in Add new Post - Admin section dropdown menu
 */
function wpapi_override_wp_dropdown_users($output) {
    global $post, $user_ID;
    //get the Admin-role users IDs
    $admins = getUsersWithRole('admin');
    //get the author-role users IDs
    $authors = getUsersWithRole('author');
    //merge the array
    $result = array_merge($admins, $authors);

    //array converted into comma seprated string
    $authorsall = implode(",", $result);

    // return if this isn't the theme author override dropdown
    if (!preg_match('/post_author_override/', $output))
        return $output;

    // return if we've already replaced the list (end recursion)
    if (preg_match('/post_author_override_replaced/', $output))
        return $output;

    // replacement call to wp_dropdown_users
    $output = wp_dropdown_users(array(
        'echo' => 0,
        'name' => 'post_author_override_replaced',
        'selected' => empty($post->ID) ? $user_ID : $post->post_author,
        'include_selected' => true,
        'include' => $authorsall
    ));

    // put the original name back
    $output = preg_replace('/post_author_override_replaced/', 'post_author_override', $output);

    return $output;
}

add_filter('wp_dropdown_users', 'wpapi_override_wp_dropdown_users');

/*
 * Find User IDs by Role
 */

function getUsersWithRole($role) {
    $wp_user_search = new WP_User_Search($usersearch, $userspage, $role);
    return $wp_user_search->get_results();
}

Using above code, you can load multiple role users in author drop down.