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我正在创建一个调查页面，其中包含可以是单选按钮列表、复选框列表或文本框的问题和答案列表。这些控件使用 Controls.Add 在其 ItemDataBound 事件中动态添加到 Repeater。

我已经成功地渲染了页面，但是当我提交表单并遍历转发器中的控件以获取单选按钮和文本框值的选定值时，FindControl 返回 null。我需要做什么才能获得选定的值？我试过迭代RepeaterItems，但也返回了null。我尝试了不同类型的 FindControl，但它从未解析控件类型。如果我像这样在Repeater中添加声明性DataBinder，它会起作用

<asp:Repeater ID="rptSurvey" runat="server" Visible="true" EnableViewState="true" >
 <ItemTemplate>
      <%# DataBinder.Eval(Container.DataItem, "Question") %>
 </ItemTemplate>
</asp:Repeater>

但是，我想动态添加控件，但是这样做我在提交时无法获取选定的值。这是我的代码的主要结构......

<html>
<asp:Repeater ID="rptSurvey" runat="server" Visible="true">                      
</asp:Repeater>
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />
</html>

protected void Page_Load(object sender, EventArgs e)
{

  ...

            if (!IsPostBack)
            {
                rptSurvey.DataSource = GetQuestions();
                rptSurvey.DataBind();
            }
  ...

}

protected void rptSurvey_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
            {
                string question = (DataBinder.Eval(e.Item.DataItem, "Question")).ToString();

              litQuestion = new Literal();
                litQuestion.Text = question;
        RadioButtonList rblAnswer = (RadioButtonList)item;


                    rptSurvey.Controls.Add(rblAnswer);
    }
}

protected void btnSubmit_Click(object sender, EventArgs e)
{
           ...
            Dictionary<int, string> answers = new Dictionary<int, string>();

            try
            {
                var list = FindControls(rptSurvey, c => c is RadioButtonList || c is CheckBoxList || c is TextBox);

                foreach (Control item in list)
                {
                    QuestionId = int.Parse(Questions.Rows[list.IndexOf(item)][0].ToString());

                    if (item is TextBox)
                    {
                        TextBox txtAnswer = (TextBox)item;
                        answers.Add(QuestionId, txtAnswer.Text);
                    }
                    else if (item is RadioButtonList)
                    {
                        RadioButtonList rblAnswer = (RadioButtonList)item;
                        answers.Add(QuestionId, rblAnswer.SelectedItem.Text);
                    }

                    else if (item is CheckBoxList)
                    {
                        // Iterate through the Items collection of the CheckBoxList 
                        string cblMultiAnswer = "";
                        for (int i = 0; i < cblAnswer.Items.Count; i++)
                        {
                            if (cblAnswer.Items[i].Selected)
                            {
                                cblMultiAnswer += cblAnswer.Items[i].Value + ",";
                            }
                        }

                        answers.Add(QuestionId, cblMultiAnswer);
                    }
                }

               bSurvey.BLInsertSurveyAnswers(answers, dateCreated, _userEmail);
            }
        }

        public static List<Control> FindControls(Control parent, Predicate<Control> match)
        {
            var list = new List<Control>();
            foreach (Control ctl in parent.Controls)
            {
                if (match(ctl))
                    list.Add(ctl);
                list.AddRange(FindControls(ctl, match));
            }
            return list;
}
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1 回答 1

1

您必须首先创建控制树（始终 - 不仅在非回发上）。在 oninit 或 onpreload 事件中执行此操作。

看这里：http ://www.4guysfromrolla.com/articles/081402-1.aspx

于 2011-01-11T12:34:19.430 回答