How to find the checked radio button in a subset container?
<p>I have a list of radio button, not radiobuttonlist, I need to find out which one is checked. The container is divs within a known wizardstep. Since only the wizardstep id is known, how to find radio button within divs under it? 
The structure is something like this:</p>

<pre><code>&lt;asp:WizardStep runat="server" ID="TypeStep" StepType="Step" Title="Business Type"&gt;
   &lt;div id="A" runat="server"&gt;
      &lt;asp:radiobutton .....

   &lt;/div&gt;
   &lt;div id="B" runat="server&gt;
      &lt;asp:radiobutton .....

   &lt;/div&gt;
    ...
&lt;/asp:WizardStep&gt;
</code></pre>

<p>My code is as follows:</p>

<pre><code>foreach (RadioButton rb in TypeStep.Controls.OfType&lt;RadioButton&gt;()){
  ...
}
</code></pre>

<p>But it can not find any radiobutton, unless I change the TypeStep to "A" div, but in my code, which div is not knew. I can only use TypeStep to search checked radiobutton.</p>

<p>Any idea?</p>
