//Notified update of node status private void Ping_Complete(object sender, PingCompletedEventArgs k) { PingReply reply = k.Reply; IGammaMachineInfo machine = k.UserState as IGammaMachineInfo; try { if (reply.Status == IPStatus.Success) { machine.UpdateNotifiableProperties(NodeState.Online); } else { machine.UpdateNotifiableProperties(NodeState.Offline); } } catch (NullReferenceException e) { machine.UpdateNotifiableProperties(NodeState.Unknown); } }