c# - Add query values to an asp Link Button -

i have link button here.

<li><asp:linkbutton id="mypdf" onclick="download_click" runat="server" text="my pdf" navigateurl='<%# "./downloadableproducts.aspx?filename=mypdf" %>'></asp:linkbutton></li> 

and doesn't work, says "could not find file". know it's query string because when put path file manually, works charm.

i have tried this:

<li><asp:linkbutton id="mypdf" onclick="download_click" runat="server" text="my pdf" navigateurl='<%# "./downloadableproducts.aspx?filename=" + eval("id") %>'></asp:linkbutton></li> 

and didn't work :(

<li>   <asp:linkbutton id="mypdf" onclick="download_click"     runat="server" text="my pdf"         navigateurl="~/downloadableproducts.aspx?filename=mypdf">   </asp:linkbutton> </li>