title: Radiobuttonlist selecteditem is always null
body: <p>Quiz project, a question has a radiobuttonlist with either 2 items(T/F) or 4 items (a,b,c,d)
  number of questions varies. Panel is used to show only one question at a time (show/hide).
  after answering all questions user clicks on submit button and all answers should be saved in database. In code behind selecteditem is always null and value is always empty string.</p>
  
  <pre><code>&lt;asp:DataList ID="dtQuestion" runat="server" RepeatDirection="Vertical" OnItemDataBound="FormatDataListRow" &gt;
          &lt;ItemTemplate&gt;
              &lt;asp:Panel id="panel" runat="server" BorderColor="#536895" BorderStyle="Solid" BorderWidth="1" style="display: none;" EnableViewState="true"&gt;
                  &lt;asp:Label id="lblQuestionDesc" runat="server" Text="" &gt;&lt;/asp:Label&gt;
                  &lt;asp:RadioButtonList id="rbl" runat="server" EnableViewState="true" &gt;    &lt;/asp:RadioButtonList&gt;
                  &lt;/asp:Panel&gt;
              &lt;/ItemTemplate&gt;                
  &lt;/asp:DataList&gt;
  </code></pre>
  
  <p>on submit click. I call a function that search the page for RBL I am able to see their correct ID's and list items but nothing is selected.</p>
  
  <pre><code> string id;
         if     (c.GetType().ToString().Equals("System.Web.UI.WebControls.RadioButtonList"))
                 {
                     if (c.ID != "rbl")
                     {
                      id = c.ID;
                      al.Add(id + "," + ((RadioButtonList)c).SelectedItem.Value); //SelectedValue);  //
                  }
              }
  </code></pre>