如何在下拉菜单中设置数据库中的值？

Question

我设法从下拉列表添加数据到数据库。我的问题是当我想编辑时，我无法看到数据库的值，我添加到下拉菜单中。我知道我的问题在于edit_class_view.php文件。

这里是我的edit_class_view.php：

<div class="form-group"> 
    <label class="control-label col-lg-2"> School Year-Semester:</label> 
     <div class="col-lg-4"> 
      <?php 
       echo form_open('main/editClass'); 
       $options = array(
        '' => 'Select School Year and Semester', 
        'SY 2016-2017 2nd Sem' => 'SY 2016-2017 2nd Sem', 
        'SY 2017 Summer' => 'SY 2017 Summer', 
        'SY 2017-2018 1st Sem' => 'SY 2017-2018 1st Sem', 
       ); 
       echo "<div class='drop_pos'>"; 
       echo form_dropdown('sys', $options, 'class="btn dropdown-toggle"', 'required="required"', 'data-toggle="dropdown-menu"', '<?php echo $row->$School_Year_Semester;?>'); 
       ?> 
       <br> 
       <div class="text-danger"><?php echo form_error('sys'); 
       </div> 
       </div> 
     </div> 
</div> 

Answer 1

考虑您正在使用笨3.请参阅的form_dropdown https://www.codeigniter.com/userguide3/helpers/form_helper.html

你需要做样改变正确的语法。你有<?php echo $row->$School_Year_Semester;?>

$行错字错误 - > $ School_Year_Semester应该$按行> School_Year_Semester

$selected = 'CSE'; // default value 
// check if row is set while editing; get its value 
if (isset($row->School_Year_Semester)) { 
    $selected = $row->School_Year_Semester; 
} 

// Set all other attributes for dropdown 
$attribures = array("class" => "btn dropdown-toggle", 
    "required" => "required" , "data-toggle" => "dropdown-menu"); 

echo form_dropdown('sys', $options, $selected, $attributes);