Enable checkbox when user clicks on Edit button (GridView)

Question

Hello,

I have the following code:

protected void gv_RowEditing(object sender, GridViewEditEventArgs e)
       {
           gv.EditIndex = e.NewEditIndex;

           ImageButton lnkRowSelection = (ImageButton)sender;
           String result = lnkRowSelection.CommandArgument.ToString();

           if(result=="N/A")

          //cbResultManualΝο on gridView must be set to enable.
         // cbResultManualYes on gridView must be set to enable.

            bindGrid();
       }

<asp:GridView ID="gv" runat="server" AutoGenerateColumns="false"
    OnRowCancelingEdit="gv_RowCancelingEdit"
    OnRowEditing="gv_RowEditing"
    OnRowUpdating="gv_RowUpdating"  CssClass="mTable">
    <Columns>
        <asp:TemplateField HeaderText="Check" ItemStyle-Width="25">
        <ItemTemplate>
             <asp:Label ID="lblResultAuto" runat="server" Text='<%#Eval("CheckRes") %>' Width="25"></asp:Label>
         </ItemTemplate>
    </asp:TemplateField>
            <asp:TemplateField HeaderText="Valid" ItemStyle-Width="25">
        <ItemTemplate>
         <asp:CheckBox ID="lblResultManual" runat="server" Enabled="False" />
        </ItemTemplate>
        <EditItemTemplate>
             <asp:CheckBox ID="cbResultManualYes" runat="server" Enabled="false"/>
        </EditItemTemplate>
    </asp:TemplateField>
    <asp:TemplateField HeaderText="Not Valid" ItemStyle-Width="25">
        <ItemTemplate>
         <asp:CheckBox ID="lblResultManual1" runat="server" Enabled="False" />
        </ItemTemplate>
        <EditItemTemplate>
             <asp:CheckBox ID="cbResultManualΝο" runat="server" Enabled="false"/>
        </EditItemTemplate>
    </asp:TemplateField>
         <asp:TemplateField >
            <ItemTemplate>
                <asp:LinkButton ID="btnEdit" Text="Edit" runat="server" CommandName="Edit" />
            </ItemTemplate>
            <EditItemTemplate>
                <asp:LinkButton ID="btnUpdate" Text="Update" runat="server" CommandName="Update" />
                <asp:LinkButton ID="btnCancel" Text="Cancel" runat="server" CommandName="Cancel" />
            </EditItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

How can I enable cbResultManualΝο and cbResultManualΝο when the user clicks on Edit?