ASP.NET

DataTable dt = new DataTable();
dt.Columns.Add("ID");
dt.Columns.Add("Name");
dt.Columns.Add("Year");

foreach (string se in sec)
                       {
                           DataRow dr = dt.NewRow();
                           Name[] sf = Name.FindByID(se.ID);
                           dr["ID"] = se.ID;
                           dr["Name"] =  se.Name;
                           dr["Year"] = se.Term;
                           dt.Rows.Add(dr);
                       }

DataView dv = dt.DefaultView;
rptParent.DataSource = dv;
rptParent.DataBind();

<asp:Repeater ID = "rptParent" runat="server"
   onitemdatabound="rptParent_ItemDataBound"
   onitemcommand="rptParent_ItemCommand" >
       <ItemTemplate>
           <li>
               <asp:Label ID = "lbl_Year" runat="server" Text='<%# Eval("Year") %>'/>
           </li>
           <asp:Repeater ID = "rptChild" runat="server" >
               <ItemTemplate>
                   <ul>
                       <li>
                           <asp:LinkButton ID ="lnk_Name" runat="server" Text='<%# Eval("Name") %>' CommandName = "GoToPage" CommandArgument ='<%# Eval("ID") %>'/>
                       </li>
                   </ul>
               </ItemTemplate>
           </asp:Repeater>

       </ItemTemplate>

   </asp:Repeater>

protected void rptParent_ItemDataBound(object sender, RepeaterItemEventArgs e)
        {
            RepeaterItem item = e.Item;
           
                rptChild = (Repeater)item.FindControl("rptChild");
                DataRowView drv = (DataRowView)item.DataItem;
                rptChild.DataSource = drv.CreateChildView("rptParent");
                rptChild.DataBind();
           
        }

rptParent.Items.Count

rptChild.DataSource = drv.CreateChildView("rptParent");