Gridview highlight and then select the row in a new window

My Grid name is Grid1
Protected Sub Grid1_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles Grid1.DataBound
        Try
            Session("custsuperid") = customers.SelectedValue
            For Each gr As GridViewRow In Grid1.Rows
                For Each tc As TableCell In gr.Cells
                    Dim lbluser As Label = CType(tc.FindControl("txt_userid"), Label)
                    lbluser.Attributes.Add("onclick", "javascript:ShowContent('" + lbluser.Text + "');")

                Next
            Next
            Session("viewing") = "yes"
        Catch ex As Exception
            ErrorMessage(ex.Message)
        End Try
    End Sub

Javascript function

 function ShowContent(param)
    {
      var accn=param;
      window.open("UserDetails.aspx?NAC=" + accn ,'AccountDescription','width=1080, height=650, menubar=no, resizable=no,scrollbars=yes');
     }
     

I cannot seem to get it to work.  Is there someone that help me

thank you once again for all of your help

Attached is my code:

I am getting an error message stating Conversion from string "test.aspx?querystring1=" to type 'Double' is not valid.

The column that I am selecting is datatype int.  It seems to work if I use varchar, but I need it to work with the ID

<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
    <style type="text/css">
        .style3
        {
            width: 259px;
        }
    </style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <asp:Label ID="Label1" runat="server" Text="Open Cases" Font-Bold="True" 
        Font-Names="Arial" Font-Size="Small"></asp:Label>
    <br />
    <br />
    <table id="table1" style="width:100%;" width="100%">
        <tr>
            <td id="tdLeft">
                &nbsp;</td>
            <td id="tdCenter" class="style3" align="center" style="text-align: center">
                <asp:GridView ID="GridView1" runat="server" HorizontalAlign="Center" 
                    Width="597px" Font-Names="Arial" Font-Size="Small">
                    <Columns>
                    <asp:TemplateField>
                    <ItemTemplate>
                    <asp:HyperLink ID="HyperLink1" runat="server" Text='<%# Eval("Case ID") %>'
                       NavigateUrl='<%# "test.aspx?querystring1=" + Eval("Case ID") %>'></asp:HyperLink>
                     </ItemTemplate>
                    
                    </asp:TemplateField>
                    
                    </Columns>
                    <SelectedRowStyle BackColor="#0066FF" />
                    <AlternatingRowStyle BackColor="Silver" />
              
                
                </asp:GridView>
            </td>
            <td id="tdRight">
                &nbsp;</td>
        </tr>
        </table>
    
    
    
 
 
</asp:Content>

Select allOpen in new window

OK well I got something to work, but I do not think it is the best way.  Also it is not highlighting the row it is putting a select hyperlink on the screen

Please review my code and let me know if there is another way

Thank you for all of your help

<%@ Page Title="" Language="VB" MasterPageFile="~/MasterPage.master" AutoEventWireup="false" CodeFile="OpenCases.aspx.vb" Inherits="OpenCases" %>
 
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
    <style type="text/css">
        .style3
        {
            width: 259px;
        }
    </style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
    <asp:Label ID="Label1" runat="server" Text="Open Cases" Font-Bold="True" 
        Font-Names="Arial" Font-Size="Small"></asp:Label>
    <br />
    <br />
    <table id="table1" style="width:100%;" width="100%">
        <tr>
            <td id="tdLeft">
                &nbsp;</td>
            <td id="tdCenter" class="style3" align="center" style="text-align: center">
                <asp:GridView ID="GridView1" runat="server" HorizontalAlign="Center" 
                    Width="597px" Font-Names="Arial" Font-Size="Small">
                    <Columns>
                    <asp:TemplateField>
                    <ItemTemplate>
                    <asp:HyperLink ID="Link" runat="server" ForeColor="Blue" Text='<%# Eval("Case ID") %>'>
                       </asp:HyperLink>
                     </ItemTemplate>
                    
                    </asp:TemplateField>
                    
                    </Columns>
                    <SelectedRowStyle BackColor="#0066FF" />
                    <AlternatingRowStyle BackColor="Silver" />
              
                
                </asp:GridView>
            </td>
            <td id="tdRight">
                &nbsp;</td>
        </tr>
        </table>
 
 
 
</asp:Content>
 
Code behind:
Protected Sub GridView1_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView1.RowDataBound
        If e.Row.RowType = DataControlRowType.DataRow Then
            Dim test As String
            Dim lnkMore As HyperLink = DirectCast(e.Row.FindControl("link"), HyperLink)
            test = lnkMore.Text
            
 
            lnkMore.Text = "Select"
            lnkMore.Attributes.Add _
            ("onclick", "window.open('test.aspx?pram1=" & test & _
             "',null, 'left=400, top=100, height=250, width= 250, status=no, resizable=no, scrollbars=no, _toolbar=no,location=no, menubar=no');void(0); ")
            lnkMore.Attributes.Add("onMouseOver", "this.style.cursor='hand'")
 
            
        End If

Select allOpen in new window