DAItemGroupArguments Constructor(String,String,String,VarType,Int32,Single,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 and data type, the OPC group parameters specified by requested update rate and percent deadband, 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 dataType As VarType, _
   ByVal requestedUpdateRate As Integer, _
   ByVal percentDeadband As Single, _
   ByVal state As Object _
)

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

public DAItemGroupArguments( 
   string machineName,
   string serverClass,
   string itemId,
   VarType dataType,
   int requestedUpdateRate,
   float percentDeadband,
   object state
)

public:
DAItemGroupArguments( 
   String^ machineName,
   String^ serverClass,
   String^ itemId,
   VarType^ dataType,
   int requestedUpdateRate,
   float percentDeadband,
   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.
dataType: Specifies the data type requested. Passing OpcLabs.BaseLib.ComInterop.VarTypes.Empty means that the server's canonical data type should be used.
requestedUpdateRate: How often should the updates be received (number of milliseconds).
percentDeadband: The percent change in an item value that will cause an update.
state: The state object (can be any value supplied by your code); available in event notifications.

Example

CSharp

// This example shows how subscribe to changes of multiple items with percent deadband.

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

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

                Console.WriteLine("Subscribing with different percent deadbands...");
                client.SubscribeMultipleItems(
                    new[] {
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Ramp 0:100 (10 s)", 
                                VarTypes.Empty, requestedUpdateRate:100, percentDeadband:10.0f, null), 
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Ramp 0:100 (1 min)",
                                VarTypes.Empty, requestedUpdateRate:100, percentDeadband:5.0f, null),
                        });

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

        // Item changed event handler
        static void client_PercentDeadband_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        {
            if (e.Succeeded)
                Console.WriteLine("{0}: {1}", e.Arguments.ItemDescriptor.ItemId, e.Vtq);
            else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.ItemDescriptor.ItemId, e.ErrorMessageBrief);
        }
    }
}

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