PopUp PDF window on link button click. within GridView

Hi all

I  hav one GridView in that i hav 2 columns With One Label and One Link Button

InvoiceId      ViewInvoice       by clicking on ViewInvoice Link button User can open Invoice in New Page.. For This I Bind i used following code

<Columns>
                     <asp:TemplateField ItemStyle-Width="15%" HeaderStyle-HorizontalAlign="Left">
                    <HeaderTemplate>
                  Invoice
                    </HeaderTemplate>
                    <ItemTemplate>
                        <asp:Label ID="lblInvoice" runat="server"></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
<asp:TemplateField ItemStyle-Width="15%" HeaderStyle-HorizontalAlign="Left">
                    <HeaderTemplate>
                  Invoice Status
                    </HeaderTemplate>
                    <ItemTemplate>
                        <asp:Label ID="lblInStatus" runat="server" />
                        <asp:LinkButton ID="lnkstatus" runat="server" CssClass="inputHighlighted" CommandName="cmdstatus"  CommandArgument = "<%# ((GridViewRow) Container).RowIndex %>" Visible="false">|<font color="black">Invoice payments</font></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>Code behind

Code behind

protected void GvInvoice_RowDataBound1(object sender, GridViewRowEventArgs e)
        {
             DService.IN_Invoices inv = e.Row.DataItem as DService.IN_Invoices;


            if (inv != null)
            {
                Label lblInvoice = (Label)e.Row.FindControl("lblInvoice");
               
                if (lblInvoice != null)
                {
                    lblInvoice.Text = Convert.ToString(inv.In_id);
                }

            }
 if (inv != null)
            {
                
                LinkButton lblAction = (LinkButton)e.Row.FindControl("lblAction");
               
                int status = inv.In_current_status;
                if (lblAction != null)
                {
                    lblAction.Text = "View Invoice(PDF)";
                   
                   
                }

protected void ViewInvoice(object sender, CommandEventArgs e)
        {
           int count=GvInvoice.Rows.Count;
        
               GridViewRow row = GvInvoice.Rows[1];
                Label  in_id=row.Cells[1].FindControl("lblInvoice") as Label  ;
           
                if(in_id!=null)
                {
            string invid=in_id.Text;
            string URL_Invoice = "~/Invoices/" + invid + ".pdf?in_id={0}";

            Response.Write("<script>");
            Response.Write("window.open('URL_Invoice','e.CommandArgument.ToString()')");
            Response.Write("</script>");
}

here im trying to get invoiceId throgh lblInvoice andmy invoices are atored as same as invoiceno.Pdf...  ImUnable to open That
 InvoiceinnewWindowButIf i useBelowLineIts working fine.

Response.Redirect(string.Format(URL_Invoice, e.CommandArgument.ToString()));

WatShould i do to invoice get open innew window
ThanksInAdavance