组合框不会显示MySQL的值

问题描述：

I am trying to fill a combo box from a custom table in Wordpress. print_r(array_values($cellco_options)) returns the expected array of 15 items. My foreach statement is a problem. If I echo the variables the combobox will not fill with items. If I remove the echo the combox fills with 15 items but they are blank.

Questions: Why is echo not allowing the box to fill? How can I fill my box with items I can see, is echo the wrong method in this case?

    <?php 
    global $wpdb;
    $cellco_options=$wpdb->get_results("SELECT `id`, `cellco` FROM `ea_cellcarrier` WHERE 1"); 
    ?>

    <p>
        <label for="cell_carrier<?php $template->the_instance(); ?>"><?php _e( 'Cell Carrier', 'theme-my-login' ) ?></label>

        <select type="text" name="cell_carrier" id="cell_carrier<?php $template->the_instance(); ?>" tabindex="20" />
            <option disabled selected value=""> -- select -- </option>
                <?php 
                    foreach ($cellco_options as $id => $cellco) { ?>
                    <option value= "<?php echo $id; ?>"><?php echo $cellco; ?></option>
                <?php   }
                ?>
        </select>           
    </p>

我正在尝试从Wordpress中的自定义表填充组合框。 print_r（array_values（$ cellco_options）） code>返回15个项目的预期数组。我的 foreach code>语句是个问题。如果我回显变量，组合框将不会填充项目。如果我删除回声，则combox会填充15个项目，但它们是空白的。 p>

问题：为什么echo不允许填充框？如何填写我的框中的项目？在这种情况下可以看到，回显错误的方法吗？ p>


 ＆lt;？php 
 global $ wpdb; 
 $ cellco_options = $ wpdb-＆gt; get_results（“SELECT  `id`，`cellco` FROM`ea_cellcarrier` WHERE 1“）;  
？＆gt; 
 
＆lt; p＆gt; 
＆lt; label for =“cell_carrier＆lt;？php $ template-＆gt; the_instance（）;？＆gt;”＆gt;＆lt;？php _e（'Cell Carrier'  ，'theme-my-login'）？＆gt;＆lt; / label＆gt; 
 
＆lt; select type =“text”name =“cell_carrier”id =“cell_carrier＆lt;？php $ template-＆gt; the_instance（）;  ？＆gt;”中 tabindex =“20”/＆gt; 
＆lt; option disabled selected value =“”＆gt;  - 选择 - ＆lt; / option＆gt; 
＆lt;？php 
 foreach（$ cellco_options as $ id =＆gt; $ cellco）{？＆gt; 
＆lt; option value =“＆lt;？php echo $ id  ;＆gt;“＆gt;＆lt;？php echo $ cellco;  ？＆gt;＆lt; / option＆gt; 
＆lt;？php} 
？＆gt; 
＆lt; / select＆gt;  
＆lt; / p＆gt; 
  code>  pre> 
  div>

答

Thank you miken32, I tried your tip and still had the blank spaces, however, your tip led to the following solution that works:

    global $wpdb;
    $cellco_options=$wpdb->get_results("SELECT `id`, `cellco` FROM `ea_cellcarrier` WHERE 1"); 
    ?>

    <p>
        <label for="cell_carrier<?php echo $template->the_instance(); ?>"><?php _e( 'Cell Carrier', 'theme-my-login' ) ?></label>
        <select type="text" name="cell_carrier" id="cell_carrier<?php echo $template->the_instance(); ?>" tabindex="20">
            <option selected value="" > -- select -- </option>
                <?php foreach ($cellco_options as $option):?>
                    <option value="<?php echo $option->id; ?>" >
                    <?php echo $option->cellco; ?></option>
                <?php endforeach; ?>
        </select>
    </p>

答

Your database results are not indexed by id so your foreach loop was not getting what you expected.

Also note the alternative syntax I used with the foreach() loop. It can be much easier to read in cases like this where you're mixing your PHP with HTML.

<?php 
global $wpdb;
$cellco_options=$wpdb->get_results("SELECT `id`, `cellco` FROM `ea_cellcarrier`", ARRAY_N); 
?>

<p>
    <label for="cell_carrier<?php echo $template->the_instance(); ?>"><?php _e( 'Cell Carrier', 'theme-my-login' ) ?></label>
    <select type="text" name="cell_carrier" id="cell_carrier<?php $template->the_instance(); ?>" tabindex="20">
        <option disabled="disabled" selected="selected" value=""> -- select -- </option>
<?php foreach ($cellco_options as $option):?>
        <option value= "<?php echo $option[0]?>"><?php echo $option[1]?></option>
<?php endforeach;?>
    </select>           
</p>

答

Your select html tag is closed at the end of the line.

And you can use php alternative syntax for the code.

  <?php 
    global $wpdb;
    $cellco_options=$wpdb->get_results("SELECT `id`, `cellco` FROM `ea_cellcarrier` WHERE 1"); 
    ?>

    <p>
        <label for="cell_carrier<?php echo $template->the_instance(); ?>"><?php _e( 'Cell Carrier', 'theme-my-login' ) ?></label>

        <select type="text" name="cell_carrier" id="cell_carrier<?php echo $template->the_instance(); ?>" tabindex="20">
            <option disabled selected value=""> -- select -- </option>
                <?php foreach ($cellco_options as $id => $cellco): ?>
                    <option value="<?php echo $id; ?>"><?php echo $cellco; ?></option>
                <?php endforeach; ?>
        </select>
    </p>

组合框不会显示MySQL的值

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