dentro all'evento updating
if (e.Row.RowType == DataControlRowType.Header)
{
//l'header
GridViewRow headerRow = e.Row;

foreach (TableCell cell in e.Row.Cells)
{
foreach (Control ctl in cell.Controls)
{
if (ctl.GetType().BaseType == typeof(LinkButton) && ((LinkButton)ctl).Text == "Delete")
}