Display all category with its subcategory on gridview

<asp:GridView ID="GridView1" runat="server" CellPadding="4"  ><Columns>
           <asp:TemplateField>
           <ItemTemplate>
              <table>
              <tr>
              <td>
               </table> <asp:Label ID="catagory" runat="server" Text=""></asp:Label>
              </td>
              <td>
                  <asp:GridView ID="GridView2" runat="server">
                  <Columns>
                  <asp:TemplateField>
                  <ItemTemplate>
                      <asp:Label ID="subcatagory" runat="server" Text=""></asp:Label>
                  </ItemTemplate>
                  </asp:TemplateField>
                  </Columns>
                  </asp:GridView>
              </td>
              </tr>


           </ItemTemplate>
           </asp:TemplateField>
           </Columns>

       </asp:GridView>