SubscribeDataSet(IEasyUASubscriber,UADataSetSubscriptionDescriptor) Method

Subscribes to a dataset, using a dataset subscription descriptor.

Syntax

[Extension()]
public static int SubscribeDataSet( 
   IEasyUASubscriber subscriber,
   UADataSetSubscriptionDescriptor dataSetSubscriptionDescriptor
)

[Extension()]
public:
static int SubscribeDataSet( 
   IEasyUASubscriber^ subscriber,
   UADataSetSubscriptionDescriptor^ dataSetSubscriptionDescriptor
)

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function SubscribeDataSet( _
   ByVal subscriber As IEasyUASubscriber, _
   ByVal dataSetSubscriptionDescriptor As UADataSetSubscriptionDescriptor _
) As Integer

'Usage
 
Dim subscriber As IEasyUASubscriber
Dim dataSetSubscriptionDescriptor As UADataSetSubscriptionDescriptor
Dim value As Integer
 
value = IEasyUASubscriberExtension.SubscribeDataSet(subscriber, dataSetSubscriptionDescriptor)

Parameters

subscriber

The subscriber object that will perform the operation.

This is typically the EasyUASubscriber object.

The value of this parameter cannot be null (Nothing in Visual Basic).

dataSetSubscriptionDescriptor

Contains information needed to subscribe to a dataset.

The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

Returns a dataset subscription handle that can be used to change the subscription, obtain its arguments, or unsubscribe.

Exceptions

Exception Description

Exception	Description
System.ArgumentNullException	A `null` reference (`Nothing` in Visual Basic) is passed to a method that does not accept it as a valid argument. This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

System.ArgumentNullException

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

Remarks

This is an extension method (info: C#, VB.NET). In languages that have support for extensions methods (such as C# and VB.NET), you can use the extension method as if it were a regular method on the object that is its first parameter. In other languages (such as with Python.NET), you will call the extension as a static method, and pass it the object on which it acts as its first parameter.

This method operates (at least in part) asynchronously, with respect to the caller. The actual execution of the operation may be delayed, and the outcome of the operation (if any) is provided to the calling code using an event notification, callback, or other means explained in the text. In a properly written program, this method does not throw any exceptions. You should therefore not put try/catch statements or similar constructs around calls to this method. The only exceptions thrown by this method are for usage errors, i.e. when your code violates the usage contract of the method, such as passing in invalid arguments or calling the method when the state of the object does not allow it. Any operation-related errors (i.e. errors that depend on external conditions that your code cannot reliably check) are indicated by the means the operation returns its outcome (if any), which is described in the text. For more information, see Do not catch any exceptions with asynchronous or multiple-operation methods.

Example

// This example shows how to subscribe to dataset messages with RawData field encoding, specifying the metadata necessary
// for their decoding directly in the code.
//
// In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
// https://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using System.Collections.Generic;
using System.Threading;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.PubSub;
using OpcLabs.EasyOpc.UA.PubSub.Configuration;
using OpcLabs.EasyOpc.UA.PubSub.OperationModel;

namespace UASubscriberDocExamples.PubSub._EasyUASubscriber
{
    partial class SubscribeDataSet
    {
        public static void Metadata()
        {
            // Define the PubSub connection we will work with. Uses implicit conversion from a string.
            UAPubSubConnectionDescriptor pubSubConnectionDescriptor = "opc.udp://239.0.0.1";
            // In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
            // the statement below. Your actual interface name may differ, of course.
            //pubSubConnectionDescriptor.ResourceAddress.InterfaceName = "Ethernet";

            // Define the filter. Publisher Id (unsigned 16-bits) is 30, and the writer group Id is 101.
            // The dataset writer Id (1) must not be specified in the filter, because it does not appear in the message.
            var filter = new UASubscribeDataSetFilter(UAPublisherId.CreateUInt16(30), writerGroupDescriptor: 101);

            // Define the metadata, with the use of collection initializer for its fields.
            var metaData = new UADataSetMetaData
            {
                new UAFieldMetaData("BoolToggle", UABuiltInType.Boolean),
                new UAFieldMetaData("Int32", UABuiltInType.Int32),
                new UAFieldMetaData("Int32Fast", UABuiltInType.Int32),
                new UAFieldMetaData("DateTime", UABuiltInType.DateTime)
            };

            // Define the dataset subscription, with specific communication parameters.
            // The dataset offset is needed with messages that do not contain dataset writer Ids and use RawData field
            // encoding. An exception to this rule is when the dataset is the only or first in the dataset message payload,
            // which is also the case here, but we are specifying the dataset offset anyway, for illustration.
            var dataSetSubscriptionDescriptor = new UADataSetSubscriptionDescriptor(
                pubSubConnectionDescriptor, filter, metaData)
            {
                CommunicationParameters = { UadpDataSetReaderMessageParameters = { DataSetOffset = 15 }}
            };

            // Instantiate the subscriber object and hook events.
            var subscriber = new EasyUASubscriber();
            subscriber.DataSetMessage += subscriber_DataSetMessage_Metadata;

            Console.WriteLine("Subscribing...");
            subscriber.SubscribeDataSet(dataSetSubscriptionDescriptor);

            Console.WriteLine("Processing dataset message events for 20 seconds...");
            Thread.Sleep(20 * 1000);

            Console.WriteLine("Unsubscribing...");
            subscriber.UnsubscribeAllDataSets();

            Console.WriteLine("Waiting for 1 second...");
            // Unsubscribe operation is asynchronous, messages may still come for a short while.
            Thread.Sleep(1 * 1000);

            Console.WriteLine("Finished.");
        }

        static void subscriber_DataSetMessage_Metadata(object sender, EasyUADataSetMessageEventArgs e)
        {
            // Display the dataset.
            if (e.Succeeded)
            {
                // An event with null DataSetData just indicates a successful connection.
                if (!(e.DataSetData is null))
                {
                    Console.WriteLine();
                    Console.WriteLine($"Dataset data: {e.DataSetData}");
                    foreach (KeyValuePair<string, UADataSetFieldData> pair in e.DataSetData.FieldDataDictionary)
                        Console.WriteLine(pair);
                }
            }
            else
            {
                Console.WriteLine();
                Console.WriteLine($"*** Failure: {e.ErrorMessageBrief}");
            }
        }

        // Example output:
        //
        //Subscribing...
        //Processing dataset message events for 20 seconds...
        //
        //Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
        //[BoolToggle, False {System.Boolean}; Good]
        //[Int32, 3072 {System.Int32}; Good]
        //[Int32Fast, 894 {System.Int32}; Good]
        //[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
        //
        //Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
        //[BoolToggle, False {System.Boolean}; Good]
        //[Int32, 3072 {System.Int32}; Good]
        //[Int32Fast, 920 {System.Int32}; Good]
        //[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
        //
        //Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
        //[BoolToggle, False {System.Boolean}; Good]
        //[Int32, 3073 {System.Int32}; Good]
        //[Int32Fast, 1003 {System.Int32}; Good]
        //[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
        //
        //Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
        //[BoolToggle, False {System.Boolean}; Good]
        //[Int32, 3073 {System.Int32}; Good]
        //[Int32Fast, 1074 {System.Int32}; Good]
        //[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
        //
        //Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
        //[BoolToggle, True {System.Boolean}; Good]
        //[Int32, 3074 {System.Int32}; Good]
        //[Int32Fast, 1140 {System.Int32}; Good]
        //[DateTime, 10/1/2019 12:21:16 PM {System.DateTime}; Good]
        //
        //...
    }
}

' This example shows how to subscribe to dataset messages with RawData field encoding, specifying the metadata necessary
' for their decoding directly in the code.
'
' In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
' https://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.PubSub
Imports OpcLabs.EasyOpc.UA.PubSub.Configuration
Imports OpcLabs.EasyOpc.UA.PubSub.OperationModel

Namespace PubSub._EasyUASubscriber
    Partial Friend Class SubscribeDataSet
        Public Shared Sub Metadata()

            ' Define the PubSub connection we will work with. Uses implicit conversion from a string.
            Dim pubSubConnectionDescriptor As UAPubSubConnectionDescriptor = "opc.udp://239.0.0.1"
            ' In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
            ' the statement below. Your actual interface name may differ, of course.
            ' pubSubConnectionDescriptor.ResourceAddress.InterfaceName = "Ethernet"

            ' Define the filter. Publisher Id (unsigned 16-bits) is 30, and the writer group Id is 101.
            ' The dataset writer Id (1) must not be specified in the filter, because it does not appear in the message.
            Dim filter = New UASubscribeDataSetFilter(UAPublisherId.CreateUInt16(30))
            filter.WriterGroupDescriptor.WriterGroupId = 101

            ' Define the metadata, with the use of collection initializer for its fields.
            Dim metaData = New UADataSetMetaData From {
                New UAFieldMetaData("BoolToggle", UABuiltInType.Boolean),
                New UAFieldMetaData("Int32", UABuiltInType.Int32),
                New UAFieldMetaData("Int32Fast", UABuiltInType.Int32),
                New UAFieldMetaData("DateTime", UABuiltInType.DateTime)
            }

            ' Define the dataset subscription, with specific communication parameters.
            ' The dataset offset is needed with messages that do not contain dataset writer Ids and use RawData field
            ' encoding. An exception to this rule is when the dataset is the only or first in the dataset message payload,
            ' which is also the case here, but we are specifying the dataset offset anyway, for illustration.
            Dim dataSetSubscriptionDescriptor = New UADataSetSubscriptionDescriptor(
                pubSubConnectionDescriptor, filter, metaData)
            dataSetSubscriptionDescriptor.CommunicationParameters.UadpDataSetReaderMessageParameters.DataSetOffset = 15

            ' Instantiate the subscriber object and hook events.
            Dim subscriber = New EasyUASubscriber()
            AddHandler subscriber.DataSetMessage, AddressOf subscriber_DataSetMessage_Metadata

            Console.WriteLine("Subscribing...")
            subscriber.SubscribeDataSet(dataSetSubscriptionDescriptor)

            Console.WriteLine("Processing dataset message events for 20 seconds...")
            Threading.Thread.Sleep(20 * 1000)

            Console.WriteLine("Unsubscribing...")
            subscriber.UnsubscribeAllDataSets()

            Console.WriteLine("Waiting for 1 second...")
            ' Unsubscribe operation is asynchronous, messages may still come for a short while.
            Threading.Thread.Sleep(1 * 1000)

            Console.WriteLine("Finished...")
        End Sub

        Private Shared Sub subscriber_DataSetMessage_Metadata(ByVal sender As Object, ByVal e As EasyUADataSetMessageEventArgs)
            ' Display the dataset.
            If e.Succeeded Then
                ' An event with null DataSetData just indicates a successful connection.
                If e.DataSetData IsNot Nothing Then
                    Console.WriteLine()
                    Console.WriteLine($"Dataset data: {e.DataSetData}")
                    For Each pair As KeyValuePair(Of String, UADataSetFieldData) In e.DataSetData.FieldDataDictionary
                        Console.WriteLine(pair)
                    Next
                End If
            Else
                Console.WriteLine()
                Console.WriteLine($"*** Failure: {e.ErrorMessageBrief}")
            End If
        End Sub
    End Class

    ' Example output
    '
    'Subscribing...
    'Processing dataset message events for 20 seconds...
    '
    'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
    '[BoolToggle, False {System.Boolean}; Good]
    '[Int32, 3072 {System.Int32}; Good]
    '[Int32Fast, 894 {System.Int32}; Good]
    '[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
    '
    'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
    '[BoolToggle, False {System.Boolean}; Good]
    '[Int32, 3072 {System.Int32}; Good]
    '[Int32Fast, 920 {System.Int32}; Good]
    '[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
    '
    'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
    '[BoolToggle, False {System.Boolean}; Good]
    '[Int32, 3073 {System.Int32}; Good]
    '[Int32Fast, 1003 {System.Int32}; Good]
    '[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
    '
    'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
    '[BoolToggle, False {System.Boolean}; Good]
    '[Int32, 3073 {System.Int32}; Good]
    '[Int32Fast, 1074 {System.Int32}; Good]
    '[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
    '
    'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
    '[BoolToggle, True {System.Boolean}; Good]
    '[Int32, 3074 {System.Int32}; Good]
    '[Int32Fast, 1140 {System.Int32}; Good]
    '[DateTime, 10/1/2019 12:21:16 PM {System.DateTime}; Good]
    '
    '...

End Namespace

// This example shows how to subscribe to dataset messages with RawData field encoding, specifying the metadata necessary
// for their decoding directly in the code.
//
// In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
// https://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

type
  TSubscriberEventHandlers78 = class
    procedure OnDataSetMessage(
      ASender: TObject;
      sender: OleVariant;
      const eventArgs: _EasyUADataSetMessageEventArgs);
  end;

class procedure SubscribeDataSet.Metadata;
var
  ConnectionDescriptor: _UAPubSubConnectionDescriptor;
  Field1, Field2, Field3, Field4: _UAFieldMetaData;
  MetaData: _UADataSetMetaData;
  SubscribeDataSetArguments: _EasyUASubscribeDataSetArguments;
  Subscriber: TEasyUASubscriber;
  SubscriberEventHandlers: TSubscriberEventHandlers78;
begin
  // Define the PubSub connection we will work with.
  SubscribeDataSetArguments := CoEasyUASubscribeDataSetArguments.Create;
  ConnectionDescriptor := SubscribeDataSetArguments.DataSetSubscriptionDescriptor.ConnectionDescriptor;
  ConnectionDescriptor.ResourceAddress.ResourceDescriptor.UrlString := 'opc.udp://239.0.0.1';
  // In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
  // the statement below. Your actual interface name may differ, of course.
  //ConnectionDescriptor.ResourceAddress.InterfaceName := 'Ethernet';

  // Define the filter. Publisher Id (unsigned 16-bits) is 30, and the writer group Id is 101.
  // The dataset writer Id (1) must not be specified in the filter, because it does not appear in the message.
  SubscribeDataSetArguments.DataSetSubscriptionDescriptor.Filter.PublisherId.SetUint16Identifier(30);
  SubscribeDataSetArguments.DataSetSubscriptionDescriptor.Filter.WriterGroupDescriptor.WriterGroupId := 101;

  // Define the metadata. For UADP, the order of field metadata must correspond to the order of fields in the dataset message.
  MetaData := CoUADataSetMetaData.Create;
  //
  Field1 := CoUAFieldMetaData.Create;
  Field1.BuiltInType := UABuiltInType_Boolean;
  Field1.Name := 'BoolToggle';
  MetaData.Add(Field1);
  //
  Field2 := CoUAFieldMetaData.Create;
  Field2.BuiltInType := UABuiltInType_Int32;
  Field2.Name := 'Int32';
  MetaData.Add(Field2);
  //
  Field3 := CoUAFieldMetaData.Create;
  Field3.BuiltInType := UABuiltInType_Int32;
  Field3.Name := 'Int32Fast';
  MetaData.Add(Field3);
  //
  Field4 := CoUAFieldMetaData.Create;
  Field4.BuiltInType := UABuiltInType_DateTime;
  Field4.Name := 'DateTime';
  MetaData.Add(Field4);
  //
  SubscribeDataSetArguments.DataSetSubscriptionDescriptor.DataSetMetaData := MetaData;

  // Define the specific communication parameters for the dataset subscription.
  // The dataset offset is needed with messages that do not contain dataset writer Ids and use RawData field
  // encoding. An exception to this rule is when the dataset is the only or first in the dataset message payload,
  // which is also the case here, but we are specifying the dataset offset anyway, for illustration.
  SubscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.UadpDataSetReaderMessageParameters.DataSetOffset := 15;

  // Instantiate the subscriber object and hook events.
  Subscriber := TEasyUASubscriber.Create(nil);
  SubscriberEventHandlers := TSubscriberEventHandlers78.Create;
  Subscriber.OnDataSetMessage := SubscriberEventHandlers.OnDataSetMessage;

  WriteLn('Subscribing...');
  Subscriber.SubscribeDataSet(SubscribeDataSetArguments);

  WriteLn('Processing dataset message for 20 seconds...');
  PumpSleep(20*1000);

  WriteLn('Unsubscribing...');
  Subscriber.UnsubscribeAllDataSets;

  WriteLn('Waiting for 1 second...');
  // Unsubscribe operation is asynchronous, messages may still come for a short while.
  PumpSleep(1*1000);

  WriteLn('Finished.');
  FreeAndNil(Subscriber);
  FreeAndNil(SubscriberEventHandlers);
end;

procedure TSubscriberEventHandlers78.OnDataSetMessage(
  ASender: TObject;
  sender: OleVariant;
  const eventArgs: _EasyUADataSetMessageEventArgs);
var
  Count: Cardinal;
  DictionaryEntry2: _DictionaryEntry2;
  Element: OleVariant;
  FieldDataDictionaryEnumerator: IEnumVariant;
begin
  // Display the dataset.
  if eventArgs.Succeeded then
  begin
    // An event with null DataSetData just indicates a successful connection.
    if eventArgs.DataSetData <> nil then
    begin
      WriteLn;
      WriteLn('Dataset data: ', eventArgs.DataSetData.ToString);
      FieldDataDictionaryEnumerator := eventArgs.DataSetData.FieldDataDictionary.GetEnumerator;
      while (FieldDataDictionaryEnumerator.Next(1, Element, Count) = S_OK) do
      begin
        DictionaryEntry2 := IUnknown(Element) as _DictionaryEntry2;
        WriteLn(DictionaryEntry2.ToString);
      end;
    end;
  end
  else begin
    WriteLn;
      WriteLn('*** Failure: ', eventArgs.ErrorMessageBrief);
  end;
end;

// Example output:
//
//Subscribing...
//Processing dataset message events for 20 seconds...
//
//Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
//[BoolToggle, False {System.Boolean}; Good]
//[Int32, 3072 {System.Int32}; Good]
//[Int32Fast, 894 {System.Int32}; Good]
//[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
//
//Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
//[BoolToggle, False {System.Boolean}; Good]
//[Int32, 3072 {System.Int32}; Good]
//[Int32Fast, 920 {System.Int32}; Good]
//[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
//
//Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
//[BoolToggle, False {System.Boolean}; Good]
//[Int32, 3073 {System.Int32}; Good]
//[Int32Fast, 1003 {System.Int32}; Good]
//[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
//
//Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
//[BoolToggle, False {System.Boolean}; Good]
//[Int32, 3073 {System.Int32}; Good]
//[Int32Fast, 1074 {System.Int32}; Good]
//[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
//
//Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
//[BoolToggle, True {System.Boolean}; Good]
//[Int32, 3074 {System.Int32}; Good]
//[Int32Fast, 1140 {System.Int32}; Good]
//[DateTime, 10/1/2019 12:21:16 PM {System.DateTime}; Good]
//
//...

Rem This example shows how to subscribe to dataset messages with RawData field encoding, specifying the metadata necessary
Rem for their decoding directly in the code.
Rem
Rem In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
Rem https://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.
Rem
Rem Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Rem OPC client and subscriber examples in VBScript on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBScript .
Rem Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
Rem a commercial license in order to use Online Forums, and we reply to every post.

Option Explicit

Const UABuiltInType_Boolean = 1
Const UABuiltInType_Int32 = 6
Const UABuiltInType_DateTime = 13

' Define the PubSub connection we will work with.
Dim SubscribeDataSetArguments: Set SubscribeDataSetArguments = CreateObject("OpcLabs.EasyOpc.UA.PubSub.OperationModel.EasyUASubscribeDataSetArguments")
Dim ConnectionDescriptor: Set ConnectionDescriptor = SubscribeDataSetArguments.DataSetSubscriptionDescriptor.ConnectionDescriptor
ConnectionDescriptor.ResourceAddress.ResourceDescriptor.UrlString = "opc.udp://239.0.0.1"
' In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
' the statement below. Your actual interface name may differ, of course.
' ConnectionDescriptor.ResourceAddress.InterfaceName = "Ethernet"

' Define the filter. Publisher Id (unsigned 16-bits) is 30, and the writer group Id is 101.
' The dataset writer Id (1) must not be specified in the filter, because it does not appear in the message.
SubscribeDataSetArguments.DataSetSubscriptionDescriptor.Filter.PublisherId.SetUInt16Identifier 30
SubscribeDataSetArguments.DataSetSubscriptionDescriptor.Filter.WriterGroupDescriptor.WriterGroupId = 101

' Define the metadata. For UADP, the order of field metadata must correspond to the order of fields in the dataset message.
Dim MetaData: Set MetaData = CreateObject("OpcLabs.EasyOpc.UA.PubSub.Configuration.UADataSetMetaData")
'
Dim Field1: Set Field1 = CreateObject("OpcLabs.EasyOpc.UA.PubSub.Configuration.UAFieldMetaData")
Field1.BuiltInType = UABuiltInType_Boolean
Field1.Name = "BoolToggle"
MetaData.Add(Field1)
'
Dim Field2: Set Field2 = CreateObject("OpcLabs.EasyOpc.UA.PubSub.Configuration.UAFieldMetaData")
Field2.BuiltInType = UABuiltInType_Int32
Field2.Name = "Int32"
MetaData.Add(Field2)
'
Dim Field3: Set Field3 = CreateObject("OpcLabs.EasyOpc.UA.PubSub.Configuration.UAFieldMetaData")
Field3.BuiltInType = UABuiltInType_Int32
Field3.Name = "Int32Fast"
MetaData.Add(Field3)
'
Dim Field4: Set Field4 = CreateObject("OpcLabs.EasyOpc.UA.PubSub.Configuration.UAFieldMetaData")
Field4.BuiltInType = UABuiltInType_DateTime
Field4.Name = "DateTime"
MetaData.Add(Field4)
'
Set SubscribeDataSetArguments.DataSetSubscriptionDescriptor.DataSetMetaData = MetaData

' Define the specific communication parameters for the dataset subscription.
' The dataset offset is needed with messages that do not contain dataset writer Ids and use RawData field
' encoding. An exception to this rule is when the dataset is the only or first in the dataset message payload,
' which is also the case here, but we are specifying the dataset offset anyway, for illustration.
SubscribeDataSetArguments.DataSetSubscriptionDescriptor.CommunicationParameters.UadpDataSetReaderMessageParameters.DataSetOffset = 15

' Instantiate the subscriber object and hook events.
Dim Subscriber: Set Subscriber = CreateObject("OpcLabs.EasyOpc.UA.PubSub.EasyUASubscriber")
WScript.ConnectObject Subscriber, "Subscriber_"

WScript.Echo "Subscribing..."
Subscriber.SubscribeDataSet SubscribeDataSetArguments

WScript.Echo "Processing dataset message events for 20 seconds..."
WScript.Sleep 20*1000

WScript.Echo "Unsubscribing..."
Subscriber.UnsubscribeAllDataSets

WScript.Echo "Waiting for 1 second..."
' Unsubscribe operation is asynchronous, messages may still come for a short while.
WScript.Sleep 1*1000

WScript.Echo "Finished."



Sub Subscriber_DataSetMessage(Sender, e)
    ' Display the dataset.
    If e.Succeeded Then
        ' An event with null DataSetData just indicates a successful connection.
        If Not (e.DataSetData Is Nothing) Then
            WScript.Echo
            WScript.Echo "Dataset data: " & e.DataSetData
            Dim Pair: For Each Pair in e.DataSetData.FieldDataDictionary
                WScript.Echo Pair
            Next
        End If
    Else
        WScript.Echo
        WScript.Echo "*** Failure: " & e.ErrorMessageBrief
    End If
End Sub



' Example output:
'
'Subscribing...
'Processing dataset message events for 20 seconds...
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3072 {System.Int32}; Good]
'[Int32Fast, 894 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3072 {System.Int32}; Good]
'[Int32Fast, 920 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3073 {System.Int32}; Good]
'[Int32Fast, 1003 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3073 {System.Int32}; Good]
'[Int32Fast, 1074 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, True {System.Boolean}; Good]
'[Int32, 3074 {System.Int32}; Good]
'[Int32Fast, 1140 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:16 PM {System.DateTime}; Good]
'
'...

REM This example shows how to subscribe to dataset messages with RawData field encoding, specifying the metadata necessary
REM for their decoding directly in the code.
REM
REM In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
REM https://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.
REM
REM Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
REM OPC client and subscriber examples in Visual Basic on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VB .
REM Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
REM a commercial license in order to use Online Forums, and we reply to every post.

' The subscriber object, with events
'Public WithEvents Subscriber3 As EasyUASubscriber

Private Sub EasyUASubscriber_SubscribeDataSet_Metadata_Command_Click()
    OutputText = ""

    ' Define the PubSub connection we will work with.
    Dim subscribeDataSetArguments As New EasyUASubscribeDataSetArguments
    Dim ConnectionDescriptor As UAPubSubConnectionDescriptor
    Set ConnectionDescriptor = subscribeDataSetArguments.dataSetSubscriptionDescriptor.ConnectionDescriptor
    ConnectionDescriptor.ResourceAddress.ResourceDescriptor.UrlString = "opc.udp://239.0.0.1"
    ' In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
    ' the statement below. Your actual interface name may differ, of course.
    'ConnectionDescriptor.ResourceAddress.InterfaceName := 'Ethernet';

    ' Define the filter. Publisher Id (unsigned 16-bits) is 30, and the writer group Id is 101.
    ' The dataset writer Id (1) must not be specified in the filter, because it does not appear in the message.
    Call subscribeDataSetArguments.dataSetSubscriptionDescriptor.Filter.PublisherId.SetUInt16Identifier(30)
    subscribeDataSetArguments.dataSetSubscriptionDescriptor.Filter.WriterGroupDescriptor.WriterGroupId = 101

    ' Define the metadata. For UADP, the order of field metadata must correspond to the order of fields in the dataset message.
    Dim metaData As New UADataSetMetaData
    '
    Dim field1 As New UAFieldMetaData
    field1.BuiltInType = UABuiltInType_Boolean
    field1.Name = "BoolToggle"
    metaData.Add field1
    '
    Dim field2 As New UAFieldMetaData
    field2.BuiltInType = UABuiltInType_Int32
    field2.Name = "Int32"
    metaData.Add field2
    '
    Dim field3 As New UAFieldMetaData
    field3.BuiltInType = UABuiltInType_Int32
    field3.Name = "Int32Fast"
    metaData.Add field3
    '
    Dim field4 As New UAFieldMetaData
    field4.BuiltInType = UABuiltInType_DateTime
    field4.Name = "DateTime"
    metaData.Add field4
    '
    Set subscribeDataSetArguments.dataSetSubscriptionDescriptor.DataSetMetaData = metaData
    
    ' Define the specific communication parameters for the dataset subscription.
    ' The dataset offset is needed with messages that do not contain dataset writer Ids and use RawData field
    ' encoding. An exception to this rule is when the dataset is the only or first in the dataset message payload,
    ' which is also the case here, but we are specifying the dataset offset anyway, for illustration.
    subscribeDataSetArguments.dataSetSubscriptionDescriptor.CommunicationParameters.UadpDataSetReaderMessageParameters.DataSetOffset = 15
    
    ' Instantiate the subscriber object and hook events.
    Set Subscriber3 = New EasyUASubscriber
    
    OutputText = OutputText & "Subscribing..." & vbCrLf
    Call Subscriber3.SubscribeDataSet(subscribeDataSetArguments)

    OutputText = OutputText & "Processing dataset message for 20 seconds..." & vbCrLf
    Pause 20000

    OutputText = OutputText & "Unsubscribing..." & vbCrLf
    Subscriber3.UnsubscribeAllDataSets

    OutputText = OutputText & "Waiting for 1 second..." & vbCrLf
    ' Unsubscribe operation is asynchronous, messages may still come for a short while.
    Pause 1000

    Set Subscriber3 = Nothing

    OutputText = OutputText & "Finished." & vbCrLf
End Sub

Private Sub Subscriber3_DataSetMessage(ByVal sender As Variant, ByVal eventArgs As EasyUADataSetMessageEventArgs)
    ' Display the dataset
    If eventArgs.Succeeded Then
        ' An event with null DataSetData just indicates a successful connection.
        If Not eventArgs.DataSetData Is Nothing Then
            OutputText = OutputText & vbCrLf
            OutputText = OutputText & "Dataset data: " & eventArgs.DataSetData & vbCrLf
            Dim dictionaryEntry2 : For Each dictionaryEntry2 In eventArgs.DataSetData.FieldDataDictionary
                OutputText = OutputText & dictionaryEntry2 & vbCrLf
            Next
        End If
    Else
        OutputText = OutputText & vbCrLf
        OutputText = OutputText & "*** Failure: " & eventArgs.ErrorMessageBrief & vbCrLf
    End If
End Sub
' Example output:
'
'Subscribing...
'Processing dataset message events for 20 seconds...
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3072 {System.Int32}; Good]
'[Int32Fast, 894 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3072 {System.Int32}; Good]
'[Int32Fast, 920 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:14 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3073 {System.Int32}; Good]
'[Int32Fast, 1003 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, False {System.Boolean}; Good]
'[Int32, 3073 {System.Int32}; Good]
'[Int32Fast, 1074 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:15 PM {System.DateTime}; Good]
'
'Dataset data: Good; Data; publisher=(UInt16)30, group=101, fields: 4
'[BoolToggle, True {System.Boolean}; Good]
'[Int32, 3074 {System.Int32}; Good]
'[Int32Fast, 1140 {System.Int32}; Good]
'[DateTime, 10/1/2019 12:21:16 PM {System.DateTime}; Good]
'
'...

# This example shows how to subscribe to dataset messages with RawData field encoding, specifying the metadata necessary
# for their decoding directly in the code.
#
# In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
# https://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
# a commercial license in order to use Online Forums, and we reply to every post.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import time

# Import .NET namespaces.
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.PubSub import *
from OpcLabs.EasyOpc.UA.PubSub.Configuration import *
from OpcLabs.EasyOpc.UA.PubSub.OperationModel import *


def dataSetMessage(sender, e):
    # Display the dataset.
    if e.Succeeded:
        # An event with null DataSetData just indicates a successful connection.
        if e.DataSetData is not None:
            print('')
            print('Dataset data: ', e.DataSetData, sep='')
            for pair in e.DataSetData.FieldDataDictionary:
                print(pair)
    else:
        print('')
        print('*** Failure: ', e.ErrorMessageBrief, sep='')


# Define the PubSub connection we will work with. Uses implicit conversion from a string.
pubSubConnectionDescriptor = UAPubSubConnectionDescriptor.op_Implicit('opc.udp://239.0.0.1')
# In some cases you may have to set the interface (network adapter) name that needs to be used, similarly to
# the statement below. Your actual interface name may differ, of course.
#pubSubConnectionDescriptor.ResourceAddress.InterfaceName = 'Ethernet'

# Define the filter. Publisher Id (unsigned 16-bits) is 30, and the writer group Id is 101.
# The dataset writer Id (1) must not be specified in the filter, because it does not appear in the message.
filter = UASubscribeDataSetFilter(UAPublisherId.CreateUInt16(30),
                                  UAWriterGroupDescriptor(101))

# Define the metadata.
metaData = UADataSetMetaData()
metaData.Add(UAFieldMetaData('BoolToggle', UABuiltInType.Boolean))
metaData.Add(UAFieldMetaData('Int32', UABuiltInType.Int32))
metaData.Add(UAFieldMetaData('Int32Fast', UABuiltInType.Int32))
metaData.Add(UAFieldMetaData('DateTime', UABuiltInType.DateTime))

# Define the dataset subscription, with specific communication parameters.
# The dataset offset is needed with messages that do not contain dataset writer Ids and use RawData field
# encoding. An exception to this rule is when the dataset is the only or first in the dataset message payload,
# which is also the case here, but we are specifying the dataset offset anyway, for illustration.
dataSetSubscriptionDescriptor = UADataSetSubscriptionDescriptor(pubSubConnectionDescriptor, filter, metaData)
dataSetSubscriptionDescriptor.CommunicationParameters.UadpDataSetReaderMessageParameters.DataSetOffset = 15

# Instantiate the subscriber object and hook events.
subscriber = EasyUASubscriber()
subscriber.DataSetMessage += dataSetMessage

print('Subscribing...')
subscriber.SubscribeDataSet(EasyUASubscribeDataSetArguments(dataSetSubscriptionDescriptor))

print('Processing dataset message events for 20 seconds...')
time.sleep(20)

print('Unsubscribing...')
subscriber.UnsubscribeAllDataSets()

print('Waiting for 1 second...')
# Unsubscribe operation is asynchronous, messages may still come for a short while.
time.sleep(1)

subscriber.DataSetMessage -= dataSetMessage

print('Finished.')

Requirements

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

Reference

IEasyUASubscriberExtension Class
IEasyUASubscriberExtension Members
Overload List

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