[SerializableAttribute()] 
public class Detail 

class MyPage : System.Web.UI.Page
{
   public void RenderDetails(DetailCollection Details, Dynamicweb.Rendering.Template ParentTemplate, string LoopName)
   {
       if (ParentTemplate.LoopExists(LoopName))
       {
           Dynamicweb.Rendering.Template DetailTemplate = ParentTemplate.GetLoop(LoopName);

           foreach (Detail dtl in Details)
           {
               RenderDetail(dtl, DetailTemplate);
               DetailTemplate.CommitLoop();
           }
       }
   }

   private void RenderDetail(Detail dtl, Dynamicweb.Rendering.Template template)
   {
       //TODO: insert your code here
   }
}