public void Stop()
        {
            /*
             * 取消 CrowdRealTimeEvent 事件
             * stop
             */

            if (m_vm != null)
            {
                WinFormAppUtil.AppContainer.Instance.EvtAggregator.GetEvent <CrowdRealTimeEvent>().Unsubscribe(OnSearchResultReturned);
                m_vm.StopCrowdRealtime();
                m_vm = null;
            }
        }