private void lb_MouseMove(object sender, MouseEventArgs e) { string strTip = ""; //Get the item ListBoxArticle lba = sender as ListBoxArticle; int nIdx = lba.IndexFromPoint(e.Location); if ((nIdx >= 0) && (nIdx < lba.Items.Count)) { strTip = lba.Items[nIdx].ToString(); } if (strTip != tooltip.GetToolTip(lba)) { tooltip.SetToolTip(lba, strTip); } }