php - 在选择框中保留所选值

Question

如何在从数据库动态填充的选择框中保留我选择的选项。我看过很多答案，但大多数都是针对静态值的。这是我的代码，

  <select name="batchnumber" class="form-control"  id="batchno" required>   

         <option value="">select batch number</option>                 
       <?php 
            $sql = mysql_query("SELECT DISTINCT rpp_regn_bulkbatch_no,rpp_id FROM tbl_regn_prescribed_parameters where rpp_regn_bulkbatch_no  != 0");
                  while ($row = mysql_fetch_assoc($sql)){   

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

Answer 1

你好，我们可以简单地通过添加 if 条件来做到这一点，

while ($row = mysql_fetch_assoc($sql))
{   
    if($_REQUEST['batchnumber'] == $row['rpp_regn_bulkbatch_no'])
    {
        echo "<option selected value=" . $row['rpp_regn_bulkbatch_no'] . ">" . $row['rpp_regn_bulkbatch_no'] . "</option>";       
    }
    else
    {
        echo "<option value=" . $row['rpp_regn_bulkbatch_no'] . ">" . $row['rpp_regn_bulkbatch_no'] . "</option>";  
    }

}

但尝试使用 mysqli_* 函数而不是 mysql_*