private void timerLoadChat_Tick(object sender, EventArgs e)
 {
     _time--;
     if (_time <= 0)
     {
         if (Visible)
         {
             var cacXeDangChat = CuocGoi.EnVangVIP_DienThoai_LayCacXeDangChat(g_LinesDuocCapPhep);
             if (cacXeDangChat != null && cacXeDangChat.Count > 0)
             {
                 SetVehiclesToGrid(cacXeDangChat);
                 bool continueChatting = false;
                 foreach (var xe in cacXeDangChat)
                 {
                     if (xe.SoHieuXe == SoHieuXeDangChat)
                     {
                         continueChatting = true;
                     }
                 }
                 if (!continueChatting)
                 {
                     SoHieuXeDangChat = string.Empty;
                     txtChatBox.Clear();
                 }
                 LoadNoiDungChat();
             }
             else
             {
                 Close();
             }
         }
     }
 }