taxonomy terms are not populating select tag options

Question

I am retrieving taxonomy terms. The code is working.
Foreach creates three options for the select tag. There are three terms. But, when I wanted to echo "selected" for each options, after selecting one. it returns odd result. What is the problem? Here is the code.

$terms = get_terms( 'department' );
    if ( ! empty( $terms ) && ! is_wp_error( $terms ) ){
        echo '<select class="widefat" name="departments">';
            foreach ( $terms as $term ) {
                echo '<option value="'. $term->name .'"'.($_POST['departments'] == $term->name) ? ' selected="selected" ' : ''.'>'. $term->name . '</option>';
            }
        echo '</select>';

    }

Returns this:

<select class="widefat" name="departments"> selected="selected"  selected="selected"  selected="selected" </select>

Custom post name: employee Taxonomy name: department There are three terms available: Web Designer, Web Developer, Graphics Designer

I am getting the taxonomy terms if I use this code.

$terms = get_terms( 'department' );
if ( ! empty( $terms ) && ! is_wp_error( $terms ) ){
  echo '<select class="widefat" name="departments">';
    foreach ( $terms as $term ) {
      $value = $term->name;
         for ($i=0; $i < count($term); $i++) { 
            echo '<option value="'
               . $value .'"'.'>'
               . $value . '</option>';
    }

}
echo '</select>';

Returns:

<select class="widefat" name="departments">
<option value="Graphic Designer">Graphic Designer</option>
<option value="Web Designer">Web Designer</option>
<option value="Web Devloper">Web Devloper</option>
</select>

But if I want to implement selected into the selected option then it is collapsing.

I want to add if you chose Graphic Designer then the option would look like

<option value="Graphic Designer" selected="selected">Graphic Designer</option>

But this is not happening.

Answer 1

I believe this has more to do with the ternary operator being used inside of string concatenation.

I would eliminate this issue by relying on a classic if statement, but WordPress provides a helpful function selected, giving us:

$terms = get_terms( 'department' );
if ( ! empty( $terms ) && ! is_wp_error( $terms ) ) {
    echo '<select class="widefat" name="departments">';
    foreach ( $terms as $term ) {
        echo '<option value="'. $term->name .'"'.selected($_POST['departments'], $term->name, false ).'>'. $term->name . '</option>';
    }
    echo '</select>';

}

However, there is something more egregious going on here that is unrelated to your question. What if we have a term named "><script>alert('hello world');</script><option>? We have an avenue for an injection attack here due to an unescaped variable output. So lets update the code with some escaping so that it's secure:

$terms = get_terms( 'department' );
if ( ! empty( $terms ) && ! is_wp_error( $terms ) ) {
    echo '<select class="widefat" name="departments">';
    foreach ( $terms as $term ) {
        echo '<option value="'. esc_attr( $term->name ) .'"'.selected($_POST['departments'], $term->name, false).'>'. esc_html( $term->name ) . '</option>';
    }
    echo '</select>';

}

Now any HTML or entities that may have been unexpectedly inserted have been made safe, and the code is secure. We can also simplify the code to make it easier to read:

$terms = get_terms( 'department' );
if ( ! empty( $terms ) && ! is_wp_error( $terms ) ) {
    echo '<select class="widefat" name="departments">';
    foreach ( $terms as $term ) {
        ?>
        <option value="<?php echo esc_attr( $term->name ); ?>"
            <?php selected($_POST['departments'], $term->name);?>>
            <?php echo esc_html( $term->name );?>
        </option>
        <?php
    }
    echo '</select>';

}

Answer 2

I think an alternative to using get_terms() is to use get_categories() instead.

Here's a snippet i did with your codes:

    $args = ['taxonomy'  => 'department'];
    $terms = get_categories($args);
    if ( ! empty( $terms ) && ! is_wp_error( $terms ) ){
    echo '<select class="widefat" name="departments">';
        foreach ( $terms as $term ) {
            echo '<option value="'. $term->name .'"'.($_POST['departments'] == $term->name) ? ' selected="selected" ' : ''.'>'. $term->name . '</option>';
        }
    echo '</select>';
}

Hope it will help you.