I worked it out based on JasonS response. What I did was create a hidden field in the Grid View like this:
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:HiddenField ID="hdID" runat="server" Value='<%# Eval("JobID") %>' />
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField Visible="False">
<ItemTemplate>
<asp:LinkButton ID="lnkSelect" runat="server" CommandName="select" Text="Select" />
</ItemTemplate>
</asp:TemplateField>
Then on the OnRowDataBind have code to set the selected row
protected virtual void Grid_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
// Click to highlight row
Control lnkSelect = e.Row.FindControl("lnkSelect");
if (lnkSelect != null)
{
StringBuilder click = new StringBuilder();
click.AppendLine(m_View.Page.ClientScript.GetPostBackClientHyperlink(lnkSelect, String.Empty));
click.AppendLine(String.Format("onGridViewRowSelected('{0}')", e.Row.RowIndex));
e.Row.Attributes.Add("onclick", click.ToString());
}
}
}
And then in the Javascript I have code like this
<script type="text/javascript">
var selectedRowIndex = null;
function onGridViewRowSelected(rowIndex)
{
selectedRowIndex = rowIndex;
}
function editItem()
{
if (selectedRowIndex == null) return;
var gridView = document.getElementById('<%= GridView1.ClientID %>');
var cell = gridView.rows[parseInt(selectedRowIndex)+1].cells[0];
var hidID = cell.childNodes[0];
window.open('JobTypeEdit.aspx?id=' + hidID.value);
}
</script>
Works a treat :-)