EventHandler OPC UA

Question

我正在尝试使用opc ua与服务器和客户端进行通信，它工作得很好，直到我希望我的程序返回值。Im使用OnNotification函数：

public void OnNotification(MonitoredItem item, MonitoredItemNotificationEventArgs e)
{
   // Debug.Log("Entre aqui");

    foreach (var value in item.DequeueValues())
    {
       // Debug.Log("Entre aqui otra vez");
        //Console.WriteLine("{0}: {1}, {2}, {3}", item.DisplayName, value.Value, value.SourceTimestamp, value.StatusCode);
        Debug.Log("{0}: {1}, {2}, {3}" + item.DisplayName + value.Value + value.SourceTimestamp + value.StatusCode);
        //rotZ = float.Parse(value.Value.ToString());
        //J1.Rotate(0, 0, rotZ);
    }
}

这是我创建监视项并将MonitoredItem EventHandler添加到函数的地方，但我不知道为什么i.Notification的事件从不发生，所以它从不运行OnNotification函数。我应该触发事件发生吗？我做错了什么？

        var filter = new EventFilter();


        var triggeringItemId = new MonitoredItem(subscription.DefaultItem)
        {
            NodeClass = NodeClass.Object,
            StartNodeId = ObjectIds.Server,
            AttributeId = Attributes.EventNotifier,
            MonitoringMode = MonitoringMode.Reporting,
            SamplingInterval = -1,
            QueueSize = 100,
            CacheQueueSize = 100,
            Filter = filter 
        };
        // Log("Step 5 - Add a list of items you wish to monitor to the subscription.");
        var list = new List<MonitoredItem> {
            triggeringItemId,
            /*
            monitoredItem,
            monitoredItem2
            */
        };

        list.ForEach(i => i.Notification += OnNotification);

        Debug.Log(list);

        subscription.AddItems(list);

        // Log("Step 6 - Add the subscription to the session.");
        session.AddSubscription(subscription);
        subscription.Create();

Answer 1

按照这个顺序，它对我来说是有效的：

session.AddSubscription(subscription);
subscription.Create();

然后我创建MonitoredItems，然后将它们添加到订阅中，这是您错过的最后一步：

subscription.ApplyChanges();

Answer 2

尝试向EventFilter添加一些“Select”子句。以下列表与基本事件类型相对应。AlarmCondition类型提供了更多的字段。

var filter =新的EventFilter()；

filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.EventType)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.SourceName)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.SourceName)；filter.AddSelectClause(ObjectTypes.BaseEventType，filter.AddSelectClause(ObjectTypes.BaseEventType，)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.EventId)；Opc.Ua.BrowseNames.EventType Opc.Ua.BrowseNames.SourceNode)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.Time)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.LocalTime)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.Message)；filter.AddSelectClause(ObjectTypes.BaseEventType，Opc.Ua.BrowseNames.Severity)；