how to bind data in asp.net using 3tier

Question

i need to use 3tier in asp.net

design


  <div id="Div1">
        <h1>Welcome</h1>
           <h3>CANCEL PRODUCTS</h3>
           <table class="style1">
            <tr>
                <td>
                    <asp:Label ID="Label1" runat="server" Text="Category"></asp:Label>
                </td>
                <td>
                    <asp:DropDownList ID="ddcan" runat="server"
                        onselectedindexchanged="ddcan_SelectedIndexChanged">
                    
                        <asp:ListItem Value="0">Select</asp:ListItem>
                    </asp:DropDownList> &nbsp;</td>
            </tr>
            <tr>
                <td align="center" colspan="2">
                    <asp:GridView ID="grdvew" runat="server"
                        onselectedindexchanged="GridView1_SelectedIndexChanged" Width="427px">
                    </asp:GridView>
                </td>
              
            </tr>
        </table>                
      </div>



in DropDownList  i have 3 list namely 1.Vegetables  2. Grocery  3.Pharmacy  ,if i choose Vegetables   a list will shown in  gridview in that i have to edit and cancel .(using link button)

i have to edit and cancel the item if i choose Vegetables   in dropdownlist. i never use storeprocedure