private IMonitorAlarm locate(int index) { if (AlarmManager != null) { mVisionAlarm = AlarmManager.Locate(index); mCurIndex = AlarmManager.Index; if (mVisionAlarm != null) { SetPreviewImage(mVisionAlarm.AlarmImage); UpdateFormState(); } else { SetPreviewImage(null); label_count.Text = ""; UpdateFormState(); } return(mVisionAlarm); } else { return(null); } }