/// <summary> /// Is used to one-time read value. /// Callback is invoked when valueStatusTimestamp.ValueStatusCode != StatusCodes.Unknown /// </summary> public ReadOnceValueSubscription(IDataAccessProvider dataProvider, string elementId, Action <ValueStatusTimestamp>?setValueAction) { _dataProvider = dataProvider; _setValueAction = setValueAction; _dataProvider.AddItem(elementId, this); }
/// <summary> /// Is used to subscribe for value updating and to write values. /// valueUpdated(oldValue, newValue) is invoked when Value property Updated. Initial Value property is new ValueStatusTimestamp(), Any(null) and Unknown status. /// </summary> public ValueSubscription(IDataAccessProvider dataAccessProvider, string elementId, Action <ValueStatusTimestamp, ValueStatusTimestamp>?valueUpdated = null) { DataAccessProvider = dataAccessProvider; ElementId = elementId; _valueUpdated = valueUpdated; DataAccessProvider.AddItem(ElementId, this); }