Php 值不会显示在下拉列表中

我想在PHP中编辑一行，其中一个字段是一个下拉列表，它将获取所选行（能力组）的值集，但问题是所选选项为空，尽管查询有效，我也可以使用print\r打印值。但是当我把它放在表单中时，它什么也没有显示

我将其用于以下形式：

<select  class="edit_competence_group" name="Competence_Group_Edit">
    <?php   
    $r=$this->matchinggroup;
    $Competence_Group=$r['Competence_Group'];
    print_r($this->matchinggroup);
    ?>
    <option selected="selected" value=<?php if (isset ($Competence_Group)) {echo $Competence_Group;}?>></option>
    <?php 
    $arr=$this->distinct_competence_groups;

    foreach ($arr as $row){

        echo "<option value='" .$row['Competence_Group']. "'>" .$row['Competence_Group'] . "</option>";         
    }
    ?>


</select>

---

试着这样做：

<select  class="edit_competence_group" name="Competence_Group_Edit">
    <?php   
    $r=$this->matchinggroup;
    $Competence_Group=$r['Competence_Group'];
    print_r($this->matchinggroup);
   if (isset ($Competence_Group))
     echo '<option value=" '.$Competence_Group.'" selected >your forgot the name here</option>';

    $arr=$this->distinct_competence_groups;

    foreach ($arr as $row){

        echo "<option value='" .$row['Competence_Group']. "'>" .$row['Competence_Group'] . "</option>";         
    }
    ?>


</select>

---

确保用双引号括住所选的

选项

值，就像对待其余元素一样。例如

…value=“”…

if(isset($_REQUEST['edit_id'])){
    echo $_GET['edit_id'];
    $oneC=$hr_object->matchingGroup($_GET['edit_id']);
    $page->assign('matchinggroup', $oneC);}

<select  class="edit_competence_group" name="Competence_Group_Edit">
    <?php   
    $r=$this->matchinggroup;
    $Competence_Group=$r['Competence_Group'];
    print_r($this->matchinggroup);
   if (isset ($Competence_Group))
     echo '<option value=" '.$Competence_Group.'" selected >your forgot the name here</option>';

    $arr=$this->distinct_competence_groups;

    foreach ($arr as $row){

        echo "<option value='" .$row['Competence_Group']. "'>" .$row['Competence_Group'] . "</option>";         
    }
    ?>


</select>