try to find out in the following way
<asp:GridView ID="grdProductList" runat="server" Width="100%" GridLines="None" AllowPaging="True">
<HeaderStyle HorizontalAlign="Center" />
<Columns>
<asp:TemplateField HeaderText="Special Price">
<ItemStyle Width="20%" HorizontalAlign="center" />
<ItemTemplate>
<asp:HyperLink runat="server" ID="hylnk_SpecialPrice" NavigateUrl='<%# "SpecialPrice.aspx?ProductID=" + Eval("iProductID") %>'
Text="Add/Edit"></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>