UnsubscribeItem Method (

Unsubscribe from OPC item, specifying its handle.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Sub UnsubscribeItem( _
   ByVal handle As Integer _
)

'Usage
 
Dim instance As _EasyDAClient
Dim handle As Integer
 
instance.UnsubscribeItem(handle)

void UnsubscribeItem( 
   int handle
)

void UnsubscribeItem( 
   int handle
)

Parameters

handle: Item subscription handle as returned by the SubscribeItem method

Example

COM

VBScript

Rem This example shows how unsubscribe from changes of a single item.
Rem
Rem Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Option Explicit

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
WScript.ConnectObject Client, "Client_"

WScript.Echo "Subscribing..."
Dim handle: handle = Client.SubscribeItem("", "OPCLabs.KitServer.2", "Simulation.Random", 1000)

WScript.Echo "Waiting for 10 seconds..."
WScript.Sleep 10*1000

WScript.Echo "Unsubscribing..."
Client.UnsubscribeItem handle

WScript.Echo "Waiting for 10 seconds..."
WScript.Sleep 10*1000



Sub Client_ItemChanged(Sender, e)
    If Not (e.Succeeded) Then
        WScript.Echo "*** Failure: " & e.ErrorMessageBrief
        Exit Sub
    End If

    WScript.Echo e.Vtq
End Sub

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

_EasyDAClient Interface
_EasyDAClient Members

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