QuickOPC User's Guide and Reference
EventNotification Event (IEasyUAClient)
Example 



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OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA Namespace > IEasyUAClient Interface : EventNotification Event
Raised for every event generated by a subscribed OPC monitored item.
Syntax
'Declaration
 

Event EventNotification As EasyUAEventNotificationEventHandler
 
'Usage
 

Dim instance As IEasyUAClient
Dim handler As EasyUAEventNotificationEventHandler
 
AddHandler instance.EventNotification, handler
Event Data

The event handler receives an argument of type EasyUAEventNotificationEventArgs containing data related to this event. The following EasyUAEventNotificationEventArgs properties provide information specific to this event.

PropertyDescription
ArgumentsHolds arguments that were used to subscribe to a monitored item in an OPC-UA server.  
DiagnosticsDiagnostics information (such as warnings) assembled during the operation. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
DiagnosticsCountCount of diagnostic information elements assembled during the operation. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
DiagnosticsSummaryTextual summary of diagnostics information, one message per line. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
ErrorIdGets or sets the error ID of the error. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
ErrorMessageGets or sets a message that describes the current exception. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
ErrorMessageBriefThe first line of the error message. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
EventDataEvent notification information.  
ExceptionGets the current exception. Contains null reference when no exception. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
NormalizedDiagnosticsA normalized OpcLabs.BaseLib.OperationModel.OperationEventArgs.Diagnostics collection. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
NormalizedExceptionA normalized OpcLabs.BaseLib.OperationModel.OperationEventArgs.Exception object, or null if there was no error. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
RefreshDenotes whether this notification was triggered by subscription refresh.  
RefreshCompleteWhen True, this notification denotes that the subscription refresh is complete.  
RefreshInitiatedWhen True, this notification denotes that the subscription refresh has been initiated.  
StatusInfoStatus information corresponding to the contents of the event arguments.  
SucceededGets indication whether the operation has succeeded. (Inherited from OpcLabs.BaseLib.OperationModel.OperationEventArgs)
Example

.NET

COM

.NET

COM

// This example shows how to subscribe to event notifications and display each incoming event.

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace.Standard;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.AlarmsAndConditions
{
    partial class SubscribeEvent
    {
        public static void Overload1()
        {
            // Define which server we will work with.
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer";

            // Instantiate the client object and hook events.
            var client = new EasyUAClient();
            client.EventNotification += client_EventNotification;

            Console.WriteLine("Subscribing...");
            client.SubscribeEvent(endpointDescriptor, UAObjectIds.Server, 1000);

            Console.WriteLine("Processing event notifications for 30 seconds...");
            System.Threading.Thread.Sleep(30 * 1000);

            Console.WriteLine("Unsubscribing...");
            client.UnsubscribeAllMonitoredItems();

            Console.WriteLine("Waiting for 5 seconds...");
            System.Threading.Thread.Sleep(5 * 1000);

            Console.WriteLine("Finished.");
        }

        static void client_EventNotification(object sender, EasyUAEventNotificationEventArgs e)
        {
            // Display the event.
            Console.WriteLine(e);
        }



        // Example output (truncated):
        //Subscribing...
        //Processing event notifications for 30 seconds...
        //[] Success
        //[] Success; Refresh; RefreshInitiated
        //[] Success; Refresh; [EastTank] 100! {DialogConditionType} "The dialog was activated" @9/9/2021 2:22:18 PM (10 fields)
        //[] Success; Refresh; [EastTank] 100! {ExclusiveDeviationAlarmType} "The alarm is active." @9/9/2021 4:19:37 PM (10 fields)
        //[] Success; Refresh; [EastTank] 500! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/9/2021 4:19:35 PM (10 fields)
        //[] Success; Refresh; [EastTank] 900! {TripAlarmType} "The alarm severity has increased." @9/9/2021 4:19:29 PM (10 fields)
        //[] Success; Refresh; [EastTank] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:39:03 PM (10 fields)
        //[] Success; Refresh; [EastTank] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:40:03 PM (10 fields)
        //[] Success; Refresh; [NorthMotor] 100! {DialogConditionType} "The dialog was activated" @9/9/2021 2:22:18 PM (10 fields)
        //[] Success; Refresh; [NorthMotor] 500! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/9/2021 4:19:35 PM (10 fields)
        //[] Success; Refresh; [NorthMotor] 900! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/9/2021 4:19:29 PM (10 fields)
        //[] Success; Refresh; [NorthMotor] 100! {TripAlarmType} "The alarm is active." @9/9/2021 4:19:32 PM (10 fields)
        //[] Success; Refresh; [NorthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:39:08 PM (10 fields)
        //[] Success; Refresh; [NorthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:40:14 PM (10 fields)
        //[] Success; Refresh; [WestTank] 100! {DialogConditionType} "The dialog was activated" @9/9/2021 2:22:18 PM (10 fields)
        //[] Success; Refresh; [WestTank] 900! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/9/2021 4:19:29 PM (10 fields)
        //[] Success; Refresh; [WestTank] 100! {NonExclusiveLevelAlarmType} "The alarm is active." @9/9/2021 4:19:32 PM (10 fields)
        //[] Success; Refresh; [WestTank] 100! {TripAlarmType} "The alarm is active." @9/9/2021 4:19:37 PM (10 fields)
        //[] Success; Refresh; [WestTank] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:38:55 PM (10 fields)
        //[] Success; Refresh; [WestTank] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:39:43 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {DialogConditionType} "The dialog was activated" @9/9/2021 2:22:18 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {ExclusiveDeviationAlarmType} "The alarm is active." @9/9/2021 4:19:32 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {NonExclusiveLevelAlarmType} "The alarm is active." @9/9/2021 4:19:37 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 500! {TripAlarmType} "The alarm severity has increased." @9/9/2021 4:19:35 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:39:51 PM (10 fields)
        //[] Success; Refresh; [SouthMotor] 100! {TripAlarmType} "The alarm severity has increased." @9/9/2021 3:38:57 PM (10 fields)
        //[] Success; Refresh; RefreshComplete
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:39 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:39 PM (10 fields)
        //[] Success; [EastTank] 100! {TripAlarmType} "The alarm was deactivated by the system." @9/9/2021 4:19:39 PM (10 fields)
        //[] Success; [NorthMotor] 100! {NonExclusiveLevelAlarmType} "The alarm was deactivated by the system." @9/9/2021 4:19:39 PM (10 fields)
        //[] Success; [WestTank] 100! {ExclusiveDeviationAlarmType} "The alarm was deactivated by the system." @9/9/2021 4:19:39 PM (10 fields)
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:40 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:40 PM (10 fields)
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:41 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:41 PM (10 fields)
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:42 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:42 PM (10 fields)
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:43 PM (10 fields)
        //[] Success; [NorthMotor] 300! {TripAlarmType} "The alarm severity has increased." @9/9/2021 4:19:43 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:43 PM (10 fields)
        //[] Success; [WestTank] 300! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/9/2021 4:19:43 PM (10 fields)
        //[] Success; [SouthMotor] 300! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/9/2021 4:19:43 PM (10 fields)
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:44 PM (10 fields)
        //[] Success; [EastTank] 700! {NonExclusiveLevelAlarmType} "The alarm severity has increased." @9/9/2021 4:19:44 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:44 PM (10 fields)
        //[] Success; [NorthMotor] 700! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/9/2021 4:19:44 PM (10 fields)
        //[] Success; [SouthMotor] 700! {TripAlarmType} "The alarm severity has increased." @9/9/2021 4:19:44 PM (10 fields)
        //[] Success; [Internal] 500! {SystemEventType} "Raising Events" @9/9/2021 4:19:45 PM (10 fields)
        //[] Success; [EastTank] 300! {ExclusiveDeviationAlarmType} "The alarm severity has increased." @9/9/2021 4:19:45 PM (10 fields)
        //[] Success; [Internal] 500! {AuditEventType} "Events Raised" @9/9/2021 4:19:45 PM (10 fields)
        //...
    }
}
// This example shows how to subscribe to event notifications and display each
// incoming event.

type
  TClientEventHandlers2 = class
    procedure OnEventNotification(
      Sender: TObject;
      sender0: OleVariant;
      eventArgs: _EasyUAEventNotificationEventArgs);
  end;

procedure TClientEventHandlers2.OnEventNotification(
  Sender: TObject;
  sender0: OleVariant;
  eventArgs: _EasyUAEventNotificationEventArgs);
begin
  // Display the event
  WriteLn(eventArgs.ToString);
end;

class procedure SubscribeEvent.Main;
var
  Client: EasyUAClient;
  EvsClient: TEvsEasyUAClient;
  ClientEventHandlers2: TClientEventHandlers2;
begin
  // Instantiate the client object and hook events
  EvsClient := TEvsEasyUAClient.Create(nil);
  Client := EvsClient.ComServer;
  ClientEventHandlers2 := TClientEventHandlers2.Create;
  EvsClient.OnEventNotification := @ClientEventHandlers2.OnEventNotification;

  WriteLn('Subscribing...');
  Client.SubscribeEvent(
    'opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer',
    'nsu=http://opcfoundation.org/UA/;i=2253',  // UAObjectIds.Server
    1000);

  WriteLn('Processing event notifications for 30 seconds...');
  PumpSleep(30*1000);

  WriteLn('Unsubscribing...');
  Client.UnsubscribeAllMonitoredItems;

  WriteLn('Waiting for 5 seconds...');
  PumpSleep(5*1000);
end;
// This example shows how to subscribe to multiple events.

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.AddressSpace.Standard;
using OpcLabs.EasyOpc.UA.AlarmsAndConditions;
using OpcLabs.EasyOpc.UA.Filtering;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.AlarmsAndConditions
{
    class SubscribeMultipleMonitoredItems
    {
        public static void Events()
        {
            // Define which server we will work with.
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer";

            // Instantiate the client object and hook events.
            var client = new EasyUAClient();
            client.EventNotification += client_EventNotification;

            Console.WriteLine("Subscribing...");
            client.SubscribeMultipleMonitoredItems(new[]
                {
                    new EasyUAMonitoredItemArguments("firstState", 
                        endpointDescriptor, 
                        UAObjectIds.Server,
                        new UAMonitoringParameters(1000, new UAEventFilterBuilder(
                            UAFilterElements.GreaterThanOrEqual(UABaseEventObject.Operands.Severity, 500),
                            UABaseEventObject.AllFields)))
                        { AttributeId = UAAttributeId.EventNotifier },
                    new EasyUAMonitoredItemArguments("secondState",
                        endpointDescriptor, 
                        UAObjectIds.Server,
                        new UAMonitoringParameters(2000, new UAEventFilterBuilder(
                            UAFilterElements.Equals(
                                UABaseEventObject.Operands.SourceNode, 
                                new UANodeId("nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=1:Metals/SouthMotor")),
                            UABaseEventObject.AllFields)))
                        { AttributeId = UAAttributeId.EventNotifier }
                });

            Console.WriteLine("Processing event notifications for 30 seconds...");
            System.Threading.Thread.Sleep(30 * 1000);

            Console.WriteLine("Unsubscribing...");
            client.UnsubscribeAllMonitoredItems();

            Console.WriteLine("Waiting for 5 seconds...");
            System.Threading.Thread.Sleep(5 * 1000);

            Console.WriteLine("Finished.");
        }

        static void client_EventNotification(object sender, EasyUAEventNotificationEventArgs e)
        {
            // Display the event
            Console.WriteLine(e);
        }
        

        // Example output (truncated):
        //Subscribing...
        //Processing monitored item changed events for 30 seconds...
        //[firstState] Success
        //[secondState] Success
        //[firstState] Success; Refresh; RefreshInitiated
        //[firstState] Success; Refresh; (10 field results) [EastTank] 500! "The alarm was acknoweledged." @10/14/2019 4:00:13 PM
        //[firstState] Success; Refresh; (10 field results) [EastTank] 500! "The alarm was acknoweledged." @10/14/2019 4:00:17 PM
        //[firstState] Success; Refresh; (10 field results) [NorthMotor] 500! "The alarm was acknoweledged." @10/14/2019 4:00:02 PM
        //[firstState] Success; Refresh; (10 field results) [NorthMotor] 500! "The alarm was acknoweledged." @10/14/2019 4:00:16 PM
        //[firstState] Success; Refresh; (10 field results) [SouthMotor] 700! "The alarm was acknoweledged." @10/14/2019 4:00:21 PM
        //[firstState] Success; Refresh; (10 field results) [SouthMotor] 500! "The alarm was acknoweledged." @10/14/2019 4:00:03 PM
        //[firstState] Success; Refresh; RefreshComplete
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:08 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:08 PM
        //[secondState] Success; Refresh; RefreshInitiated
        //[secondState] Success; Refresh; (10 field results) [SouthMotor] 100! "The dialog was activated" @9/10/2019 8:08:25 PM
        //[secondState] Success; Refresh; (10 field results) [SouthMotor] 100! "The alarm is active." @11/8/2019 7:48:07 PM
        //[secondState] Success; Refresh; (10 field results) [SouthMotor] 700! "The alarm was acknoweledged." @10/14/2019 4:00:21 PM
        //[secondState] Success; Refresh; (10 field results) [SouthMotor] 500! "The alarm was acknoweledged." @10/14/2019 4:00:03 PM
        //[secondState] Success; Refresh; (10 field results) [SouthMotor] 100! "The alarm severity has increased." @9/10/2019 8:09:02 PM
        //[secondState] Success; Refresh; (10 field results) [SouthMotor] 100! "The alarm severity has increased." @9/10/2019 8:09:59 PM
        //[secondState] Success; Refresh; RefreshComplete
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:09 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:09 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:10 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:10 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:11 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:11 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:12 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:12 PM
        //[firstState] Success; (10 field results) [EastTank] 500! "The alarm severity has increased." @11/8/2019 7:48:13 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:13 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:13 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:14 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:14 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:15 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:15 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:16 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:16 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:17 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:17 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Raising Events" @11/8/2019 7:48:18 PM
        //[firstState] Success; (10 field results) [Internal] 500! "Events Raised" @11/8/2019 7:48:18 PM
        //[secondState] Success; (10 field results) [SouthMotor] 300! "The alarm severity has increased." @11/8/2019 7:48:18 PM
        //...
    }
}
// This example shows how to subscribe to multiple events.

type
  THelperMethods19 = class
    class function ObjectTypeIds_BaseEventType: _UANodeId; static;
    class function UAFilterElements_SimpleAttribute(TypeId: _UANodeId; simpleRelativeBrowsePathString: string): _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_NodeId: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_EventId: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_EventType: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_SourceNode: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_SourceName: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_Time: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_ReceiveTime: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_LocalTime: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_Message: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_Operands_Severity: _UASimpleAttributeOperand; static;
    class function UABaseEventObject_AllFields: _UAAttributeFieldCollection; static;
  end;

type
  TClientEventHandlers19 = class
    procedure Client_EventNotification(
      ASender: TObject;
      sender: OleVariant;
      const eventArgs: _EasyUAEventNotificationEventArgs);
  end;

procedure TClientEventHandlers19.Client_EventNotification(
  ASender: TObject;
  sender: OleVariant;
  const eventArgs: _EasyUAEventNotificationEventArgs);
begin
  // Display the event
    WriteLn(eventArgs.ToString);
end;


class procedure SubscribeMultipleMonitoredItems.Events;
var
  Arguments: OleVariant;
  Client: TEasyUAClient;
  ClientEventHandlers: TClientEventHandlers19;
  EndpointDescriptor: string;
  EventFilter1, EventFilter2: _UAEventFilter;
  MonitoredItemArguments1, MonitoredItemArguments2: _EasyUAMonitoredItemArguments;
  MonitoringParameters1, MonitoringParameters2: _UAMonitoringParameters;
  Operand11, Operand21: _UASimpleAttributeOperand;
  Operand12, Operand22: _UALiteralOperand;
  ServerNodeId1, ServerNodeId2: _UANodeId;
  SourceNodeId: _UANodeId;
  WhereClause1, WhereClause2: _UAContentFilterElement;
begin
  EndpointDescriptor := 'opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer';

  // set MonitoredItemArguments1
  // Event filter: The severity is >= 500.
  Operand11 := THelperMethods19.UABaseEventObject_Operands_Severity;
  Operand12 := CoUALiteralOperand.Create;
  Operand12.Value := 500;
  WhereClause1 := CoUAContentFilterElement.Create;
  WhereClause1.FilterOperator := UAFilterOperator_GreaterThanOrEqual;
  WhereClause1.FilterOperands.Add(Operand11);
  WhereClause1.FilterOperands.Add(Operand12);

  EventFilter1 := CoUAEventFilter.Create;
  EventFilter1.SelectClauses := THelperMethods19.UABaseEventObject_AllFields;
  EventFilter1.WhereClause := WhereClause1;

  ServerNodeId1 := CoUANodeId.Create;
  ServerNodeId1.StandardName := 'Server';

  MonitoringParameters1 := CoUAMonitoringParameters.Create;
  MonitoringParameters1.EventFilter := EventFilter1;
  MonitoringParameters1.QueueSize := 1000;
  MonitoringParameters1.SamplingInterval := 1000;

  MonitoredItemArguments1 := CoEasyUAMonitoredItemArguments.Create;
  MonitoredItemArguments1.AttributeId := UAAttributeId_EventNotifier;
  MonitoredItemArguments1.EndpointDescriptor.UrlString := EndpointDescriptor;
  MonitoredItemArguments1.MonitoringParameters := MonitoringParameters1;
  MonitoredItemArguments1.NodeDescriptor.NodeId := ServerNodeId1;
  MonitoredItemArguments1.State := 'firstState';

  // set MonitoredItemArguments2
  // Event filter: The event comes from a specified source node.
  Operand21 := THelperMethods19.UABaseEventObject_Operands_SourceNode;
  SourceNodeId := CoUANodeId.Create;
  SourceNodeId.ExpandedText := 'nsu=http://opcfoundation.org/Quickstarts/AlarmCondition ;ns=2;s=1:Metals/SouthMotor';
  Operand22 := CoUALiteralOperand.Create;
  Operand22.Value := SourceNodeId;
  WhereClause2 := CoUAContentFilterElement.Create;
  WhereClause2.FilterOperator := UAFilterOperator_Equals;
  WhereClause2.FilterOperands.Add(Operand21);
  WhereClause2.FilterOperands.Add(Operand22);

  EventFilter2 := CoUAEventFilter.Create;
  EventFilter2.SelectClauses := THelperMethods19.UABaseEventObject_AllFields;
  EventFilter2.WhereClause := WhereClause2;

  ServerNodeId2 := CoUANodeId.Create;
  ServerNodeId2.StandardName := 'Server';

  MonitoringParameters2 := CoUAMonitoringParameters.Create;
  MonitoringParameters2.EventFilter := EventFilter2;
  MonitoringParameters2.QueueSize := 1000;
  MonitoringParameters2.SamplingInterval := 2000;

  MonitoredItemArguments2 := CoEasyUAMonitoredItemArguments.Create;
  MonitoredItemArguments2.AttributeId := UAAttributeId_EventNotifier;
  MonitoredItemArguments2.EndpointDescriptor.UrlString := EndpointDescriptor;
  MonitoredItemArguments2.MonitoringParameters := MonitoringParameters2;
  MonitoredItemArguments2.NodeDescriptor.NodeId := ServerNodeId2;
  MonitoredItemArguments2.State := 'secondState';


  // Instantiate the client object and hook events
  Client := TEasyUAClient.Create(nil);
  ClientEventHandlers := TClientEventHandlers19.Create;
  Client.OnEventNotification := ClientEventHandlers.Client_EventNotification;

  Arguments := VarArrayCreate([0, 1], varVariant);
  Arguments[0] := MonitoredItemArguments1;
  Arguments[1] := MonitoredItemArguments2;

  WriteLn('Subscribing...');
  Client.SubscribeMultipleMonitoredItems(Arguments);

  WriteLn('Processing monitored item changed events for 30 seconds...');
  PumpSleep(30*1000);

  WriteLn('Unsubscribing...');
  Client.UnsubscribeAllMonitoredItems;

  WriteLn('Waiting for 5 seconds...');
  Sleep(5*1000);

  WriteLn('Finished.');
  VarClear(Arguments);
  FreeAndNil(Client);
  FreeAndNil(ClientEventHandlers);
end;

class function THelperMethods19.ObjectTypeIds_BaseEventType: _UANodeId;
  var NodeId: _UANodeId;
  begin
    NodeId := CoUANodeId.Create;
    NodeId.StandardName := 'BaseEventType';
    Result := NodeId;
  end;

class function THelperMethods19.UAFilterElements_SimpleAttribute(TypeId: _UANodeId; simpleRelativeBrowsePathString: string): _UASimpleAttributeOperand;
var
  BrowsePathParser: _UABrowsePathParser;
  Operand: _UASimpleAttributeOperand;
begin
  BrowsePathParser := CoUABrowsePathParser.Create;
  Operand := CoUASimpleAttributeOperand.Create;
  Operand.TypeId.NodeId := TypeId;
  Operand.QualifiedNames := BrowsePathParser.ParseRelative(simpleRelativeBrowsePathString).ToUAQualifiedNameCollection;
  Result := Operand;
end;

class function THelperMethods19.UABaseEventObject_Operands_NodeId: _UASimpleAttributeOperand;
var
  Operand: _UASimpleAttributeOperand;
begin
  Operand := CoUASimpleAttributeOperand.Create;
  Operand.TypeId.NodeId.StandardName := 'BaseEventType';
  Operand.AttributeId := UAAttributeId_NodeId;
  Result := Operand;
end;

class function THelperMethods19.UABaseEventObject_Operands_EventId: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/EventId');
end;

class function THelperMethods19.UABaseEventObject_Operands_EventType: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/EventType');
end;

class function THelperMethods19.UABaseEventObject_Operands_SourceNode: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/SourceNode');
end;

class function THelperMethods19.UABaseEventObject_Operands_SourceName: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/SourceName');
end;

class function THelperMethods19.UABaseEventObject_Operands_Time: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/Time');
end;

class function THelperMethods19.UABaseEventObject_Operands_ReceiveTime: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/ReceiveTime');
end;

class function THelperMethods19.UABaseEventObject_Operands_LocalTime: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/LocalTime');
end;

class function THelperMethods19.UABaseEventObject_Operands_Message: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/Message');
end;

class function THelperMethods19.UABaseEventObject_Operands_Severity: _UASimpleAttributeOperand;
begin
  Result := UAFilterElements_SimpleAttribute(ObjectTypeIds_BaseEventType, '/Severity');
end;

class function THelperMethods19.UABaseEventObject_AllFields: _UAAttributeFieldCollection;
var
  Fields: _UAAttributeFieldCollection;
begin
  Fields := CoUAAttributeFieldCollection.Create;
  Fields.Add(UABaseEventObject_Operands_NodeId.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_EventId.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_EventType.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_SourceNode.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_SourceName.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_Time.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_ReceiveTime.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_LocalTime.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_Message.ToUAAttributeField);
  Fields.Add(UABaseEventObject_Operands_Severity.ToUAAttributeField);

  Result := Fields;
end;
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also

Reference

IEasyUAClient Interface
IEasyUAClient Members

 

 

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