DAItemGroupArguments Constructor(String,String,String,Int32,Object)

Initializes a new instance of the class. Initializes a new instance of the class, with the OPC server specified by machine name and server class, the OPC item specified by its ItemId, the OPC group parameters specified by requested update rate, and with a user-defined state object.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Public Function New( _
   ByVal machineName As String, _
   ByVal serverClass As String, _
   ByVal itemId As String, _
   ByVal requestedUpdateRate As Integer, _
   ByVal state As Object _
)

'Usage
 
Dim machineName As String
Dim serverClass As String
Dim itemId As String
Dim requestedUpdateRate As Integer
Dim state As Object
 
Dim instance As New DAItemGroupArguments(machineName, serverClass, itemId, requestedUpdateRate, state)

public DAItemGroupArguments( 
   string machineName,
   string serverClass,
   string itemId,
   int requestedUpdateRate,
   object state
)

public:
DAItemGroupArguments( 
   String^ machineName,
   String^ serverClass,
   String^ itemId,
   int requestedUpdateRate,
   Object^ state
)

Parameters

machineName: Name of the machine. Determines the computer on which the OPC server is located. May be an empty string, in which case the OPC server is assumed to exist on the local computer or at the computer specified for it by DCOM configuration.
serverClass: Contains ProgID of the OPC server.
itemId: Contains OPC item identifier.
requestedUpdateRate: How often should the updates be received (number of milliseconds).
state: The state object (can be any value supplied by your code); available in event notifications.

Example

CSharp
PowerShell
VB.NET

// This example shows how subscribe to changes of multiple items and display the value of the item with each change.

using System;
using System.Threading;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class SubscribeMultipleItems
    {
        public static void Main1()
        {
            // Instantiate the client object.
            using (var client = new EasyDAClient())
            {
                client.ItemChanged += client_Main1_ItemChanged;

                Console.WriteLine("Subscribing item changes...");
                client.SubscribeMultipleItems(
                    new[] {
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, null), 
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 1000, null), 
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000, null),  
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 1000, null)
                        });

                Console.WriteLine("Processing item changed events for 1 minute...");
                Thread.Sleep(60 * 1000);

                Console.WriteLine("Unsubscribing item changes...");
            }

            Console.WriteLine("Finished.");
        }

        // Item changed event handler
        static void client_Main1_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        {
            if (e.Succeeded)
                Console.WriteLine($"{e.Arguments.ItemDescriptor.ItemId}: {e.Vtq}");
            else
                Console.WriteLine($"{e.Arguments.ItemDescriptor.ItemId} *** Failure: {e.ErrorMessageBrief}");
        }
    }
}

# This example shows how subscribe to changes of multiple items and display the value of the item with each change.

#requires -Version 5.1
using namespace OpcLabs.EasyOpc.DataAccess
using namespace OpcLabs.EasyOpc.DataAccess.OperationModel

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Assemblies/net47/OpcLabs.EasyOpcClassic.dll"

# Instantiate the client object.
$client = New-Object EasyDAClient

# Item changed event handler
Register-ObjectEvent -InputObject $client -EventName ItemChanged -Action { 
    if ($EventArgs.Succeeded) {
        Write-Host "$($EventArgs.Arguments.ItemDescriptor.ItemId): $($EventArgs.Vtq)"
    }
    else {
        Write-Host "$($EventArgs.Arguments.ItemDescriptor.ItemId) *** Failure: $($EventArgs.ErrorMessageBrief)"
    }
}

Write-Host "Subscribing item changes..."
$handleArray = [IEasyDAClientExtension]::SubscribeMultipleItems($client, @(
    (New-Object DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, $null)),
    (New-Object DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 1000, $null)),
    (New-Object DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000, $null)),
    (New-Object DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 1000, $null))
    ))

Write-Host "Processing item changed events for 1 minute..."
$stopwatch =  [System.Diagnostics.Stopwatch]::StartNew() 
while ($stopwatch.Elapsed.TotalSeconds -lt 30) {    
    Start-Sleep -Seconds 1
}

Write-Host "Unsubscribing item changes..."
$client.UnsubscribeAllItems()

Write-Host "Finished."

' This example shows how subscribe to changes of multiple items and display the value of the item with each change.

Imports System.Threading
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

Namespace DocExamples.DataAccess._EasyDAClient
    Partial Friend Class SubscribeMultipleItems
        Public Shared Sub Main1()
            Using client = New EasyDAClient()
                AddHandler client.ItemChanged, AddressOf client_ItemChanged_Main1

                client.SubscribeMultipleItems(New DAItemGroupArguments() { _
                 New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, Nothing), _
                 New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 1000, Nothing), _
                 New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000, Nothing), _
                 New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 1000, Nothing) _
                })

                Console.WriteLine("Processing item changed events for 1 minute...")
                Thread.Sleep(60 * 1000)
            End Using
        End Sub

        ' Item changed event handler
        Private Shared Sub client_ItemChanged_Main1(ByVal sender As Object, ByVal e As EasyDAItemChangedEventArgs)
            ' Display the data
            If e.Succeeded Then
                Console.WriteLine("{0}: {1}", e.Arguments.ItemDescriptor.ItemId, e.Vtq)
            Else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.ItemDescriptor.ItemId, e.ErrorMessageBrief)
            End If
        End Sub
    End Class
End Namespace

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2012, Windows Server 2016; .NET Core, .NET 5, .NET 6: Linux, macOS, Microsoft Windows

Reference

DAItemGroupArguments Class
DAItemGroupArguments Members
Overload List