QuickOPC User's Guide and Reference
PullMultipleDataSetMessages Method (IEasyUASubscriber)
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.PubSub Namespace > IEasyUASubscriber Interface : PullMultipleDataSetMessages Method
Maximum number of event notifications returned.
The number of milliseconds to wait, or System.Threading.Timeout.Infinite (-1) to wait indefinitely.
Attempts to pull multiple dataset message event notifications.
Syntax
'Declaration
 
<CanBeNullAttribute()>
<EditorBrowsableAttribute(EditorBrowsableState.Advanced)>
<ElementsNotNullAttribute()>
Function PullMultipleDataSetMessages( _
   ByVal maximumCount As Integer, _
   ByVal millisecondsTimeout As Integer _
) As EasyUADataSetMessageEventArgs()
'Usage
 
Dim instance As IEasyUASubscriber
Dim maximumCount As Integer
Dim millisecondsTimeout As Integer
Dim value() As EasyUADataSetMessageEventArgs
 
value = instance.PullMultipleDataSetMessages(maximumCount, millisecondsTimeout)
[CanBeNull()]
[EditorBrowsable(EditorBrowsableState.Advanced)]
[ElementsNotNull()]
EasyUADataSetMessageEventArgs[] PullMultipleDataSetMessages( 
   int maximumCount,
   int millisecondsTimeout
)
[CanBeNull()]
[EditorBrowsable(EditorBrowsableState.Advanced)]
[ElementsNotNull()]
array<EasyUADataSetMessageEventArgs^>^ PullMultipleDataSetMessages( 
   int maximumCount,
   int millisecondsTimeout
) 

Parameters

maximumCount
Maximum number of event notifications returned.
millisecondsTimeout
The number of milliseconds to wait, or System.Threading.Timeout.Infinite (-1) to wait indefinitely.

Return Value

An array of event arguments, or null if no event is available within the specified time.
Exceptions
ExceptionDescription
The value of an argument is outside the allowable range of values as defined by the invoked method.
Example
// This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection, and pull events, and display
// the incoming datasets.
//
// In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
// http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.

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

namespace UADocExamples.PubSub._EasyUASubscriber
{
    class PullDataSetMessage
    {
        public static void Main1()
        {
            // 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";

            // Instantiate the subscriber object.
            // In order to use event pull, you must set a non-zero queue capacity upfront.
            var subscriber = new EasyUASubscriber {PullDataSetMessageQueueCapacity = 1000};

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

            Console.WriteLine("Processing dataset message events for 20 seconds...");
            int endTick = Environment.TickCount + 20 * 1000;
            do
            {
                EasyUADataSetMessageEventArgs eventArgs = subscriber.PullDataSetMessage(2 * 1000);
                if (!(eventArgs is null))
                {
                    // Display the dataset.
                    if (eventArgs.Succeeded)
                    {
                        // An event with null DataSetData just indicates a successful connection.
                        if (!(eventArgs.DataSetData is null))
                        {
                            Console.WriteLine();
                            Console.WriteLine($"Dataset data: {eventArgs.DataSetData}");
                            foreach (KeyValuePair<string, UADataSetFieldData> pair in eventArgs.DataSetData.FieldDataDictionary)
                                Console.WriteLine(pair);
                        }
                    }
                    else
                    {
                        Console.WriteLine();
                        Console.WriteLine($"*** Failure: {eventArgs.ErrorMessageBrief}");
                    }
                }
            } while (Environment.TickCount < endTick);

            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.");
        }

        // Example output:
        //
        //Subscribing...
        //Processing dataset message events for 20 seconds...
        //
        //Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
        //[#0, True {System.Boolean} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#1, 7945 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#2, 5246 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#3, 9/30/2019 11:19:14 AM {System.DateTime} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //
        //Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
        //[#0, 45 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#1, 145 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#2, 245 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#3, 345 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#4, 445 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#5, 545 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#6, 645 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#7, 745 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#8, 845 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#9, 945 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //[#10, 1045 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
        //...
    }
}
// This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection, and pull events, and display
// the incoming datasets.
//
// In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
// http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.


class procedure PullDataSetMessage.Main1;
var
  ConnectionDescriptor: _UAPubSubConnectionDescriptor;
  Count: Cardinal;
  Element: OleVariant;
  EndTick: Cardinal;
  EventArgs: _EasyUADataSetMessageEventArgs;
  PairEnumerator: IEnumVARIANT;
  SubscribeDataSetArguments: _EasyUASubscribeDataSetArguments;
  Subscriber: OpcLabs_EasyOpcUA_TLB._EasyUASubscriber;
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';

  // Instantiate the subscriber object.
  Subscriber := CoEasyUASubscriber.Create;
  // In order to use event pull, you must set a non-zero queue capacity upfront.
  Subscriber.PullDataSetMessageQueueCapacity := 1000;

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

  WriteLn('Processing dataset message events for 20 seconds...');
  EndTick := Ticks + 20*1000;
  while Ticks < EndTick do
  begin
    EventArgs := Subscriber.PullDataSetMessage(2*1000);
    if EventArgs <> nil then
      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);
            PairEnumerator := EventArgs.DataSetData.FieldDataDictionary.GetEnumerator;
            while (PairEnumerator.Next(1, Element, Count) = S_OK) do
            begin
              WriteLn(Element.ToString);
            end;
          end;
        end
        else
        begin
          WriteLn;
             WriteLn(' *** Failure: ', EventArgs.ErrorMessageBrief);
        end;
      end;
  end;

  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.');
end;

// Example output:
//
//Subscribing...
//Processing dataset message events for 20 seconds...
//
//Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
//[#0, True {System.Boolean} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#1, 7945 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#2, 5246 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#3, 9/30/2019 11:19:14 AM {System.DateTime} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//
//Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
//[#0, 45 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#1, 145 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#2, 245 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#3, 345 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#4, 445 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#5, 545 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#6, 645 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#7, 745 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#8, 845 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#9, 945 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//[#10, 1045 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
//...
# This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection, and pull events, and display
# the incoming datasets.
#
# In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
# http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.

import time
import win32com.client

# Define the PubSub connection we will work with.
subscribeDataSetArguments = win32com.client.Dispatch('OpcLabs.EasyOpc.UA.PubSub.OperationModel.EasyUASubscribeDataSetArguments')
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'

# Instantiate the subscriber object.
subscriber = win32com.client.Dispatch('OpcLabs.EasyOpc.UA.PubSub.EasyUASubscriber') 
# In order to use event pull, you must set a non-zero queue capacity upfront.
subscriber.PullDataSetMessageQueueCapacity = 1000

print('Subscribing...')
subscriber.SubscribeDataSet(subscribeDataSetArguments)

print('Processing dataset message events for 20 seconds...')
endTime = time.time() + 20
while time.time() < endTime:
    eventArgs = subscriber.PullDataSetMessage(2*1000)
    if eventArgs is not None:
        # Display the dataset.
        if eventArgs.Succeeded:
            # An event with null DataSetData just indicates a successful connection.
            if eventArgs.DataSetdata is not None:
                print('')
                print('Dataset data: ', eventArgs.DataSetData)
                for pair in eventArgs.DataSetData.FieldDataDictionary:
                    print(pair)
        else:
            print('')
            print('*** Failure: ', eventArgs.ErrorMessageBrief)

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

print('Waiting for 1 second...')
# Unsubscribe operation is asynchronous, messages may still come for a short while.
endTime = time.time() + 1
while time.time() < endTime:
    pass

print('Finished.')



# Example output:
#
#Subscribing...
#Processing dataset message events for 20 seconds...
#
##Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
#[#0, True {System.Boolean} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#1, 7945 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#2, 5246 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#3, 9/30/2019 11:19:14 AM {System.DateTime} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#
#Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
#[#0, 45 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#1, 145 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#2, 245 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#3, 345 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#4, 445 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#5, 545 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#6, 645 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#7, 745 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#8, 845 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#9, 945 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#[#10, 1045 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
#...
' This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection, and pull events, and display
' the incoming datasets.
'
' In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
' http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.

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

Namespace UADocExamples.PubSub._EasyUASubscriber
    Friend Class PullDataSetMessage
        Public Shared Sub Main1()

            ' 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"

            ' Instantiate the subscriber object.
            ' In order to use event pull, you must set a non-zero queue capacity upfront.
            Dim subscriber = New EasyUASubscriber()
            subscriber.PullDataSetMessageQueueCapacity = 1000

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

            Console.WriteLine("Processing dataset message events for 20 seconds...")
            Dim endTick As Integer = Environment.TickCount + 20 * 1000
            Do
                Dim eventArgs As EasyUADataSetMessageEventArgs = subscriber.PullDataSetMessage(2 * 1000)
                If Not eventArgs Is Nothing Then
                    ' Display the dataset.
                    If eventArgs.Succeeded Then
                        ' An event with null DataSetData just indicates a successful connection.
                        If Not eventArgs.DataSetData Is Nothing Then
                            Console.WriteLine()
                            Console.WriteLine("Dataset data: {0}", eventArgs.DataSetData)
                            For Each pair As KeyValuePair(Of String, UADataSetFieldData) In eventArgs.DataSetData.FieldDataDictionary
                                Console.WriteLine(pair)
                            Next
                        End If
                    Else
                        Console.WriteLine()
                        Console.WriteLine("*** Failure: {0}", eventArgs.ErrorMessageBrief)
                    End If
                End If
            Loop While Environment.TickCount < endTick

            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
    End Class

    ' Example output
    '
    'Subscribing...
    'Processing dataset message events for 20 seconds...
    '
    ''Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
    '[#0, True {System.Boolean} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#1, 7945 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#2, 5246 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#3, 9/30/2019 11:19:14 AM {System.DateTime} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '
    'Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
    '[#0, 45 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#1, 145 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#2, 245 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#3, 345 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#4, 445 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#5, 545 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#6, 645 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#7, 745 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#8, 845 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#9, 945 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '[#10, 1045 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
    '...

End Namespace
Rem This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection, and pull events, and display
Rem the incoming datasets.
Rem
Rem In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
Rem http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.

Option Explicit

' 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"

' Instantiate the subscriber object.
Dim Subscriber: Set Subscriber = CreateObject("OpcLabs.EasyOpc.UA.PubSub.EasyUASubscriber")
' In order to use event pull, you must set a non-zero queue capacity upfront. 
Subscriber.PullDataSetMessageQueueCapacity = 1000

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

WScript.Echo "Processing dataset message events for 20 seconds..."
Dim endTime: endTime = Now() + 20*(1/24/60/60)
Do
    Dim EventArgs: Set EventArgs = Subscriber.PullDataSetMessage(2*1000)
    If Not (EventArgs Is Nothing) Then
        ' Display the dataset.
        If EventArgs.Succeeded Then
            ' An event with null DataSetData just indicates a successful connection.
            If Not (EventArgs.DataSetData Is Nothing) Then
                WScript.Echo
                WScript.Echo "Dataset data: " & EventArgs.DataSetData
                Dim Pair: For Each Pair in EventArgs.DataSetData.FieldDataDictionary
                    WScript.Echo Pair
                Next
            End If
        Else
            WScript.Echo
            WScript.Echo "*** Failure: " & EventArgs.ErrorMessageBrief
        End If
    End If    
Loop While Now() < endTime

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."



' Example output:
'
'Subscribing...
'Processing dataset message events for 20 seconds...
'
''Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
'[#0, True {System.Boolean} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#1, 7945 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#2, 5246 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#3, 9/30/2019 11:19:14 AM {System.DateTime} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'
'Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
'[#0, 45 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#1, 145 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#2, 245 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#3, 345 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#4, 445 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#5, 545 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#6, 645 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#7, 745 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#8, 845 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#9, 945 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#10, 1045 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'...
Rem This example shows how to subscribe to all dataset messages on an OPC-UA PubSub connection, and pull events, and display
Rem the incoming datasets.
Rem
Rem In order to produce network messages for this example, run the UADemoPublisher tool. For documentation, see
Rem http://kb.opclabs.com/UADemoPublisher_Basics . In some cases, you may have to specify the interface name to be used.

Private Sub EasyUASubscriber_PullDataSetMessage_Main1_Command_Click()
    OutputText = ""
    
    ' Define the PubSub connection we will work with.
    Dim subscribeDataSetArguments: Set subscribeDataSetArguments = New 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"
    
    ' Instantiate the subscriber object.
    Dim Subscriber: Set Subscriber = New EasyUASubscriber
    ' In order to use event pull, you must set a non-zero queue capacity upfront.
    Subscriber.PullDataSetMessageQueueCapacity = 1000

    OutputText = OutputText & "Subscribing..." & vbCrLf
    Subscriber.SubscribeDataSet subscribeDataSetArguments

    OutputText = OutputText & "Processing dataset message events for 20 seconds..." & vbCrLf
    Dim endTime: endTime = Now() + 20 * (1 / 24 / 60 / 60)
    Do
        Dim eventArgs: Set eventArgs = Subscriber.PullDataSetMessage(2 * 1000)
        If Not (eventArgs Is Nothing) Then
            ' 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 Pair: For Each Pair In eventArgs.DataSetData.FieldDataDictionary
                        OutputText = OutputText & Pair & vbCrLf
                    Next
                End If
            Else
                OutputText = OutputText & vbCrLf
                OutputText = OutputText & "*** Failure: " & eventArgs.ErrorMessageBrief & vbCrLf
            End If
        End If
    Loop While Now() < endTime

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

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

    Set Subscriber = Nothing

    OutputText = OutputText & "Finished." & vbCrLf
End Sub
' Example output:
'
'Subscribing...
'Processing dataset message events for 20 seconds...
'
''Dataset data: Good; Data; publisher="32", writer=1, class=eae79794-1af7-4f96-8401-4096cd1d8908, fields: 4
'[#0, True {System.Boolean} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#1, 7945 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#2, 5246 {System.Int32} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#3, 9/30/2019 11:19:14 AM {System.DateTime} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'
'Dataset data: Good; Data; publisher="32", writer=3, class=96976b7b-0db7-46c3-a715-0979884b55ae, fields: 100
'[#0, 45 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#1, 145 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#2, 245 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#3, 345 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#4, 445 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#5, 545 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#6, 645 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#7, 745 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#8, 845 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#9, 945 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'[#10, 1045 {System.Int64} @0001-01-01T00:00:00.000 @@0001-01-01T00:00:00.000; Good]
'...
Requirements

Target Platforms: .NET Framework: Windows 10, Windows Server 2012, Windows Server 2016; .NET Core, .NET 5: Linux, macOS, Microsoft Windows

See Also

Reference

IEasyUASubscriber Interface
IEasyUASubscriber Members