How do I format a Post back including date in the title (using Linq and C# if possible)

<asp:Button ID="Btn3" runat="server" Text='<%# Eval("BkTime3", "{0: hh tt}")%>' (This works fine the postBackUrl doesn't) PostBackUrl='~/contact/VidLink.aspx?Topic=<%# Eval("BkTime3", "{0: dddd, dd MMMM, hh tt}")%>' />

I am using a ListView and it will not allow me to reference on IDs