"Trying to get properties on a non-object" in PHP

Question

I'm a WordPress theme developer and on a theme I'm working on, I've turned on debug mode and get this error inside a select drop-down box for the theme's options page.

The error says this: "Trying to get properties on a non-object." Here is the offending code:

 <select name="<?php echo $value['id']; ?>" id="<?php echo $value['id']; ?>">
                <?php foreach ($value['options'] as $option) { ?>
               <option value="<?php echo $option->term_id; ?>"  <?php if ( $settings[$id] == $option->term_id) { echo 'selected="selected"'; }?>>
                    <?php echo $option->name; ?>
                </option>                       
               <?php }?>  </select> 

I can't figure out what I'm doing wrong. The line that's specifically causing the error is this:

<option value="<?php echo $option->term_id; ?>"  <?php if ( $settings[$id] == $option->term_id) { echo 'selected="selected"'; }?>>

Thanks for any advice! :)

Answer 1

You're doing this a couple of times:

$option->someproperty

In at least one of the cases $option is not an object. When you then do -> on a non-object, you get that error.

First, verify that $option is actually an object and correct the usage if it is not.

If $option is an array then @matthewpavkov is correct, you should do $option['someproperty'] instead of $option->someproperty.

If $option is usually an object, perhaps get_categories() is sometimes returning null or false in a failure condition. Check for that before accessing $option.

Like so:

foreach ($value['options'] as $option)
{
    if ($option)
    {
        // do whatever;
    }
}

Answer 2

Execute it from action...i.e.:

function your_function(){
    YOUR CODES HEREEEEEEEEEEE............
}
ADD_ACTION('init','your_function');