QuickOPC User's Guide and Reference
PullDataSetMessageQueueCapacity Property (_EasyUASubscriber)
Example 



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OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.PubSub.ComTypes Namespace > _EasyUASubscriber Interface : PullDataSetMessageQueueCapacity Property
Capacity of the event pull queue for dataset message notifications.
Syntax
'Declaration
 

Property PullDataSetMessageQueueCapacity As Integer
 
'Usage
 

Dim instance As _EasyUASubscriber
Dim value As Integer
 
instance.PullDataSetMessageQueueCapacity = value
 
value = instance.PullDataSetMessageQueueCapacity
Example

.NET

COM

// 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]
//...
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

_EasyUASubscriber Interface
_EasyUASubscriber Members

 

 

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