protected void btnXoaCa_Click(object sender, EventArgs e) { string s = ""; foreach (ListItem i in lstChon.Items) { if (i.Selected) { s += "@" + i.Value + "@"; } } csCont.CaSauDelete(s); for (int i = lstChon.Items.Count - 1; i >= 0; i--) { if (lstChon.Items[i].Selected) { lstChon.Items.RemoveAt(i); } } btnLoad_Click(null, null); }