HTMLtableCell is not working for table header (th) in asp.net
<p>I have repeater control that have table with table header(th) and table cell(td). I want to access td and th in code. I use HTMLTableCell for both in repeater code, I can access the td, but th is not working. Any suggestions
Here is the code sample:</p>

<pre><code>&lt;asp:Repeater ID="rpt" runat="server" OnItemDataBound="repeater_ItemDataBound" &gt;
&lt;HeaderTemplate&gt;
    &lt;table id="tbl" &gt;
    &lt;thead&gt;
    &lt;tr&gt;
      &lt;th id="header1" runat="server"&gt;head 1/th&gt;
      &lt;th"&gt;Head 2&lt;/th&gt;
 &lt;/tr&gt;
    &lt;/thead&gt;  
&lt;/HeaderTemplate&gt;
&lt;ItemTemplate&gt;
    &lt;tr&gt;
      &lt;td id="td1" runat="server" &gt;&lt;asp:Literal ID="litTD1" runat="server" /&gt;&lt;/td&gt;
      &lt;td  &gt;&lt;asp:Literal ID="litTD2" runat="server" /&gt;&lt;/td&gt;
&lt;/tr&gt;
&lt;/ItemTemplate&gt;
&lt;FooterTemplate&gt;
    &lt;/table&gt;
&lt;/FooterTemplate&gt;
&lt;/asp:Repeater&gt;

in code behind

HtmlTableCell header1= e.Item.FindControl("header1") as HtmlTableCell;
HtmlTableCell td1= e.Item.FindControl("td1") as HtmlTableCell;
</code></pre>

<p>This code works for td1 (which is cell) but object null reference exception on header1
Sorry, I do have runat="server" for th</p>
