binding syntax : error : operator '&' cannot be applied to operands of type 'string' and 'object'

i am converting a vb 3.5 .net website to a 
C# .net 4  and having trouble with this binding. 
    <asp:LinkButton ID="LbtnItem2" runat="server" PostBackUrl='<%# "ANewStart.aspx?typeid=" & Eval("TypeID") & "&newsid=" & Eval("NID")%>' >