private void button1_Click(object sender, EventArgs e) { //check that fields have been filed in //add ID to the users list if (Register.Text.Equals("Unregister")) { t.RemoveEntrant(me.ID); me.RemoveTournament(t.GetID()); Register.Text = "Register"; } else if (textBox1.Text.Any() && Register.Text == "Register") { //add tag checking t.AddEntrant(new Entrant(me, textBox1.Text)); me.AddTournament(t.GetID()); Register.Text = "Unregister"; } else { label9.Text = "Please Enter a Tag"; } UpdateDisplayEntrants(); //otherwise remove the id and the user from the list of entrants }