Why is the selected drop-down box value not displayed?

Question

I'm building a function for my WordPress plugin that will display a dropdown list of all available pages. When I click "Save Changes" the values ​​are saved in the database perfectly. It also updates the value perfectly. However, the selected value is not displayed in the dropdown list. When "Save Changes" is clicked, the values ​​are saved, but the dropdown is reset to "Select One" again. It cannot display the selected option. Am I doing something wrong here? Any guidance would be greatly appreciated.

<form method=post>
<div class="header-right">
  <?php
  $posts = get_pages(
    array(
        'post_status' => 'publish',
    )
  );
  
  ?>
  <select name="page_for_logged_in" id="page_for_logged_in">
    <option selected="selected">选择一个</option>
    <?php
    foreach ( $posts as $page ) {
        ?>
        <option value="<?php echo esc_attr( $page->post_name ); ?>" <?php selected(get_option('page_for_logged_in'), 'page')?>><?php echo esc_html( $page->post_title ); ?></option>
        <?php
    }
    ?>
  </select>

  <?php
  if(empty($_POST['page_for_logged_in'])) {
      
    } else {
      $myvalue=$_POST['page_for_logged_in'];
      update_option('page_for_logged_in', $myvalue, $autoload = 'no');
    }
    ?>

<?php submit_button(); ?>

</p>
</br>
</br>
</form>

Answer 1

Ok, so I found a solution to my problem. Below is the pasted code; it may be helpful to someone.

<form method=post>
    <div class="header-right">
      <?php
      $posts = get_pages(
        array(
            'post_status' => 'publish',
        )
      );
      
      ?>
      <?php
      if(empty($_POST['page_for_logged_in'])) {
          
        } else {
          $myvalue=$_POST['page_for_logged_in'];
          update_option('page_for_logged_in', $myvalue, $autoload = 'yes');
        }
        ?>
      <select name="page_for_logged_in" id="page_for_logged_in">
        <option value="" disabled selected>选择一个</option>
        <?php
        foreach ( $posts as $page ) {
            ?>
        <option value="<?php echo esc_attr( $page->post_title ); ?>" <?php echo ( get_option('page_for_logged_in') == $page->post_title ? 'selected' : '' ); ?>><?php echo esc_html( $page->post_title ); ?></option>
            <?php
        }
        ?>
      </select>

    <?php submit_button(); ?>

    </p>
    </br>
    </br>
    </form>