我收到一条我无法修复的错误消息

Question

System.Web.HttpException: 'TextBox' 类型的'Control 'txtSearchFirstAider' 必须放在带有 runat=server 的表单标签内。'

我收到此错误，我已确保将其放置在标签内，并且我没有使用任何母版页。谁能帮忙。

这是我的后端代码。使用VB.Net

    Protected Sub btnExportPDF_Click(sender As Object, e As EventArgs)
        Response.ContentType = "application/pdf"
        Response.AddHeader("content-disposition", "attachment;filename=Panel.pdf")
        Response.Cache.SetCacheability(HttpCacheability.NoCache)
        Dim sw As New StringWriter()
        Dim hw As New HtmlTextWriter(sw)
        pnlAllFirstAiders.RenderControl(hw)
        Dim sr As New StringReader(sw.ToString())
        Dim pdfDoc As New Document(PageSize.A4, 10.0F, 10.0F, 100.0F, 0.0F)
        Dim htmlparser As New HTMLWorker(pdfDoc)
        PdfWriter.GetInstance(pdfDoc, Response.OutputStream)
        pdfDoc.Open()
        htmlparser.Parse(sr)
        pdfDoc.Close()
        Response.Write(pdfDoc)
        Response.End()
    End Sub

这是我的前端代码

<form runat="server">

<div class="col-6">
<asp:TextBox ID="txtSearchFirstAider" placeholder="search employee clock no . . . . ." ReadOnly="false" CssClass="form-control mb-2 mr-sm-2" TextMode="Search" runat="server"></asp:TextBox>
<asp:Label ID="lblSearchFirstAiderResult" Visible="false" CssClass="text-danger btn-block" runat="server" Font-Bold="true" Text="no results found !"></asp:Label>

</div>

</form>

Answer 1

感谢大家的意见，我已经设法解决了最初的问题。