This demo illustrates how to use Header(Action tmpl) and Body(Action tmpl) methods to custom the CollapsablePanel hander and body.

 Ajax.Dna().CollapsablePanel()
        .Header(() =>
        {
        %>
           <span>put you header content here.span>
        <%
        }
        .Body(() =>
        {
        %>
           <span>put you body content here.span>
        <%
        }
        .Render();