Can't save drop down select date in meta boxes

Question

I want to update my select options(drop down) but i don't know where i made a mistake.Here is my code.

<?php

function display_post_options(){

    wp_nonce_field( basename( __FILE__ ), 'post_options_nonce' ); 

?>

    <form action='' id='post-options-form' method='post'>
    Choose Your Post Layout:
    <select name='post_options_select'>
    <option id='right-sidebar' value='right' name='right_sidebar' <?php selected('post_options_select', 'right'); ?> >Right sidebar</option>
    <option id='left-sidebar' value="left" name='left_sidebar' <?php selected('post_options_select', 'left'); ?>>Left Sidebar</option>
    <option id='no-sidebar' value="no" name='no_sidebar' <?php selected('post_options_select', 'no'); ?>>No Sidebar</option>
    </select>
    </form>


<?php
}

function post_options(){
    add_meta_box( 
        'post-options',
        'Post Options',
        'display_post_options',
        'post',
        'advanced',
        'high',
        $callback_args
    );
}

function save_post_options($post_id){

    if (if_user_can_save($post_id, 'post_options_nonce')) {
        update_post_meta($post_id, 'post_options_select', $_POST['post_options_select']);
    }

}

function if_user_can_save($post_id, $nonce){

    //Check if post is autosave
    $is_autosave = wp_is_post_autosave($post_id);
    //Check if it is a Revision
    $is_revision = wp_is_post_revision($post_id);
    //Is the nonce valid
    $is_valid_nonce = ( isset( $_POST[ $nonce ] ) && wp_verify_nonce( $_POST[ $nonce ], basename( __FILE__ ) ) );
    return !($is_autosave || $is_revision) && $is_valid_nonce;

}

add_action('add_meta_boxes', 'post_options');
add_action( 'save_post', 'save_post_options', 10, 2 );
?>

UPDATE:(See comment #3) This is where i assigned my html to a variable.But it outputs (selected='selected'Choose Your Post Layout: [the select list])

function display_post_options(){
    global $post;
    wp_nonce_field( basename( __FILE__ ), 'post_options_nonce' ); 
    $post_options_select_value =  get_post_meta($post->ID,'post_options_select',true);

    $html = 'Choose Your Post Layout: ';
    $html .= '<select name="post_options_select">';
    $html .= '<option id="right-sidebar" value="right" name="right_sidebar"' . selected($post_options_select_value, 'right') . '">Right sidebar</option>';
    $html .= '<option id="left-sidebar" value="left" name="left_sidebar"' . selected($post_options_select_value, 'left') . '" >Left Sidebar</option>';
    $html .= '<option id="no-sidebar" value="no" name="no_sidebar"' . selected($post_options_select_value, 'no') . '">No Sidebar</option>';
    $html .= '</select>';

    echo $html;

}

Answer 1

First of all, You don't have to add 'form' html tag in the metabox.

You missed to pass the '$post' parameter to the function 'display_post_options' and you used selected() function wrong too. Here is the code after I updated it.

function display_post_options( $post){

wp_nonce_field( basename( __FILE__ ), 'post_options_nonce' ); 
$post_options_select_value =  get_post_meta($post->ID,'post_options_select',true);

?>


Choose Your Post Layout:
<select name='post_options_select'>
<option id='right-sidebar' value='right' name='right_sidebar' <?php selected($post_options_select_value, 'right'); ?> >Right sidebar</option>
<option id='left-sidebar' value="left" name='left_sidebar' <?php selected($post_options_select_value, 'left'); ?>>Left Sidebar</option>
<option id='no-sidebar' value="no" name='no_sidebar' <?php selected($post_options_select_value, 'no'); ?>>No Sidebar</option>
</select>

You actually need to pass the value of the meta not the key in order to 'selected ()' function work properly.

Also you need to change this line :

add_action( 'save_post', 'save_post_options', 10, 2 );

to

add_action( 'save_post', 'save_post_options', 10 );

In your case, you need just one parameter to be passed to 'save_post_options' function.

I hope this would be helpful.