Question

I have a simple .ascx file

<%@ Control Language="C#"
    AutoEventWireup="true"
    CodeFile="Profile.ascx.cs"
    Inherits="UserControls_Profile" %>
<%@ Register Assembly="RadChart.Net2"
    Namespace="Telerik.WebControls"
    TagPrefix="radC" %>
<div id="testdiv" runat="server"></div>

in code behind:

protected void Page_Load(object sender, EventArgs e) {
  Chart();
}

private void Chart() {
  testdiv.Visible=false;
}

When I try to access the page I get the exception:

error CS0103: The name ‘testdiv’ does not exist in the current context

I have tried onload as well but same result!

Answer 1

If you have an HTML div, you need to add a runat attribute like

  <div id="testDiv" runat="server">Hello world</div>

HTML elements like div’s are not ASP.NET Controls though and mixing HTML “controls” with ASP.NET might be problematic. You may prefer to do something like

  <asp:panel id="myPanel" runat="server">Hello world</asp:panel>

Update: Also check Profile.ascx.designer.cs which should be auto-generated by Visual Studio to contain “protected HtmlControl testdiv”. I assume that is missing from the partial class. I note you derive from UserControls_Profile which may be cause for confusion.