How to save select drop down wordpress metaboxes - php

Question

How to save select drop down wordpress metaboxes?
in option have a loop from my custom post type.
<select name="music[artists]" class="skant-select" id="artists" style="width: 90%;" multiple="multiple">
<?php
$artists_meta_box_args = array(
'post_type' => array('music_artist'),
//'posts_per_page' => 20,
);
$artists_meta_box = new WP_Query($artists_meta_box_args);
if ($artists_meta_box->have_posts()):
while ($artists_meta_box->have_posts()):$artists_meta_box->the_post();
global $post;
$artistFirstname = get_post_meta($post->ID, 'artist_firstname', true);
$artistLastname = get_post_meta($post->ID, 'artist_lastname', true);
?>
<option value="<?php echo $artistFirstname . '&nbsp' . $artistLastname; ?>"><?php echo $artistFirstname . '&nbsp' . $artistLastname; ?></option>
<?php
endwhile;
endif;
?>
</select>

Answer 1

I haven't tested this out yet, but I think it should work:
function save_custom_meta_box($post_id, $post, $update) {
// Check if user is allowed to edit this
if(!current_user_can("edit_post", $post_id))
return $post_id;
// Don't save meta on auto save
if(defined("DOING_AUTOSAVE") && DOING_AUTOSAVE)
return $post_id;
// Check if post-type (Change $slug to post-type metabox is in)
$slug = "post";
if($slug != $post->post_type)
return $post_id;
$meta_box_dropdown_value = "";
// If has value to save (remember to change "metabox-name" to the dropdown name).
if(isset($_POST["artist_dropdown"])) {
$meta_box_dropdown_value = $_POST["artist_dropdown"];
}
// Save the meta under meta-key "artist"
update_post_meta($post_id, "artist", $meta_box_dropdown_value);
}
add_action("save_post", "save_custom_meta_box", 10, 3);
I hope the comments are explaining it for you. Just remember to replace the values mentioned.
You will also need have to add a function to the rendered dropdown on what value to select after value is saved. So the rendered dropdown in the metabox should look something like this:
<select name="artist_dropdown">
<?php
$args = array(
'post_type' => array('music_artist')
);
$posts = get_posts($args);
$option_values = array();
if ( $posts ) {
foreach ( $posts as $post ) {
$artistFirstname = get_post_meta($post->ID, 'artist_firstname', true);
$artistLastname = get_post_meta($post->ID, 'artist_lastname', true);
$option_values[] = $artistFirstname . ' ' . $artistLastname;
}
}
foreach($option_values as $key => $value) {
if($value == get_post_meta($object->ID, "artist", true)) {
?>
<option selected><?php echo $value; ?></option>
<?php
} else {
?>
<option><?php echo $value; ?></option>
<?php
}
}
?>
</select>
Btw, here is an good tutorial on creating and saving wordpress metaboxes. You should also check out CMB2 which is an awesome toolkit for building metaboxes.