Question

我将从数据库填充的一系列下拉列表添加到后面的代码页面中。因为我需要一个可变数量的部分，每个部分包含可变数量的下拉列表，所以我必须运行我的查询然后放置构建并将HTML直接放到页面上。我确信有更好的方法可以做到这一点（可能是嵌套中继器），但正在工作。我的HTML是：

Question

<input type='hidden' id='h100' />
   <select id='q100'>
      <option>Answer 1</option>
      <option>Answer 2</option>
      <option>Answer 3</option>
  </select>

但是，当页面POST回来时，我没有在表单集合中获取这些字段。这真是奇怪，因为他们似乎昨天在那里，但后来我回到页面，找不到它们。

为什么这些不会在POST后出现在表单集合中？

我正在使用C＃代码，非常感谢任何帮助。

编辑：这是我的代码背后（请不要伤害我，我正在学习ASP.NET）：

if (!Page.IsPostBack)
    {
       // Much stuff that works fine, connecting to database, etc.

            // Get matching questions - variables
            ArrayList matchingSections = new ArrayList();
            int matchingSectionCount;

            // Get count of matching sections 
            OracleCommand cmdMatchSectCount = new OracleCommand("Select Count(distinct matching_section) From graphite.question Join graphite.q_matching Using(q_id) Where t_id = " + Session["TestTaking"].ToString(), conn);
            OracleDataReader drMatchSectCount = cmdMatchSectCount.ExecuteReader();
            drMatchSectCount.Read();
            matchingSectionCount = (int)drMatchSectCount.GetOracleNumber(0).Value;
            Session["MatchingSectionCount"] = matchingSectionCount;

            // Get matching sections
            OracleCommand cmdMatchSects = new OracleCommand("Select Distinct matching_section From graphite.question Join graphite.q_matching Using(q_id) Where t_id = " + Session["TestTaking"].ToString() + " Order By matching_Section", conn);
            OracleDataReader drMatchSects = cmdMatchSects.ExecuteReader();

            for(int i = 0; i < matchingSectionCount; i++)
            {
                drMatchSects.Read();
                matchingSections.Add(drMatchSects.GetOracleString(0).Value);
            }

            foreach (String s in matchingSections)
            {
                string row = string.Empty;
                int questionCount;
                ArrayList answers = new ArrayList();

                matchManual.InnerHtml += "\n<h2>Matching Section - " + s + "</h2>";
                matchManual.InnerHtml += "\n<table>";

                OracleCommand cmdQuestionCount = new OracleCommand("Select Count(correct_answer) From graphite.question Join graphite.q_matching Using(q_id) Where t_id = " + Session["TestTaking"].ToString() + " and matching_section = '" + s + "'", conn);
                OracleDataReader drQuestionCount = cmdQuestionCount.ExecuteReader();
                drQuestionCount.Read();
                questionCount = int.Parse(drQuestionCount.GetOracleNumber(0).Value.ToString());

                OracleCommand cmdMatchAnswers = new OracleCommand("Select correct_answer From graphite.question Join graphite.q_matching Using(q_id) Where t_id = " + Session["TestTaking"].ToString() + " and matching_section = '" + s + "' Order By correct_answer", conn);
                OracleDataReader drMatchAnswers = cmdMatchAnswers.ExecuteReader();
                for (int i = 0; i < questionCount; i++)
                {
                    drMatchAnswers.Read();
                    answers.Add(drMatchAnswers.GetOracleString(0).Value.ToString());
                }

                OracleCommand cmdMatchLoop = new OracleCommand("Select q_phrase, q_id From graphite.question Join graphite.q_matching Using(q_id) Where t_id = " + Session["TestTaking"].ToString() + " and matching_section = '" + s + "'", conn);
                OracleDataReader drMatchLoop = cmdMatchLoop.ExecuteReader();
                for (int i = 0; i < questionCount; i++)
                {
                    drMatchLoop.Read();
                    row += "\n  <tr>";
                    row += "\n    <td>" + drMatchLoop.GetOracleString(0).Value ;

                    row += "<input type='hidden' id='h" + drMatchLoop.GetOracleNumber(1).Value.ToString() + "' />";
                    row += "\n    </td>";
                    row += "\n    <td>";
                    row += "\n      <select id='q" + drMatchLoop.GetOracleNumber(1).Value.ToString() + "' runat='server'>";

                    foreach(string answer in answers)
                    {
                        row += "\n        <option>" + answer + "</option>";
                    }

                    row += "\n      </select>";
                    row += "\n    </td>";

                    row += "\n  </tr>";
                }

                matchManual.InnerHtml += row;
                matchManual.InnerHtml += "\n</table>\n\n";
   }

Answer 1

哇。只是......哇。使用<select>，您必须包含name='value'，而不是id='value'。道德：了解你的HTML。并且更加努力地寻找避免将原始HTML喷射到页面上的方法。

Answer 2

如果提交时表单集中没有它们，我认为问题是它们不在提交的表单标记内，或者您必须创建表单标记并将select标记放入其中。

@edited

啊哈 - 所以它在一个表单中，现在看看原因是select标签中缺少name属性！

表单集合在发布时使用属性名称值作为键。

Answer 3

我认为您的Page.IsPostBack条件是问题的根源。因为您只在生成元素！IsPostback =＆gt;只有'第一'时间，而不是在帖子=＆gt;之后在帖子之后他们失踪了。

下拉列表未显示在表单中

3 个答案: