ChangeMultipleMonitoredItemSubscriptions Method (

Changes parameters of multiple subscriptions, specifying objects containing all necessary arguments.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Sub ChangeMultipleMonitoredItemSubscriptions( _
   ByVal subscriptionChangeArgumentsArray As Object _
)

'Usage
 
Dim instance As _EasyUAClient
Dim subscriptionChangeArgumentsArray As Object
 
instance.ChangeMultipleMonitoredItemSubscriptions(subscriptionChangeArgumentsArray)

void ChangeMultipleMonitoredItemSubscriptions( 
   object subscriptionChangeArgumentsArray
)

void ChangeMultipleMonitoredItemSubscriptions( 
   Object^ subscriptionChangeArgumentsArray
)

Parameters

subscriptionChangeArgumentsArray

Array of OpcLabs.EasyOpc.UA.OperationModel.EasyUASubscriptionChangeArguments. Array of arguments, one element per each monitored item involved in the operation.

The value of this parameter cannot be null (Nothing in Visual Basic).

The individual elements of the parameter value cannot be null (Nothing in Visual Basic).

Exceptions

Exception Description

Exception	Description
System.ArgumentException	One of the arguments provided to a method is not valid. This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.
System.ArgumentNullException	A `null` reference (`Nothing` in Visual Basic) is passed to a method that does not accept it as a valid argument. This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

System.ArgumentException

One of the arguments provided to a method is not valid.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

System.ArgumentNullException

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

Remarks

The user-defined state, as given in OpcLabs.BaseLib.OperationModel.OperationArguments.State property of OpcLabs.EasyOpc.UA.OperationModel.EasyUAMonitoredItemArguments when subscribing to the monitored item, cannot be changed. The OpcLabs.BaseLib.OperationModel.OperationArguments.State property of OpcLabs.EasyOpc.UA.OperationModel.EasyUASubscriptionChangeArguments in the OpcLabs.EasyOpc.UA.IEasyUAClient.ChangeMultipleMonitoredItemSubscriptions method call is not used.

When you use this method, the OpcLabs.EasyOpc.UA.OperationModel.EasyUADataChangeNotificationEventArgs.Arguments or OpcLabs.EasyOpc.UA.OperationModel.EasyUAEventNotificationEventArgs.Arguments in the event notifications and callbacks may, during the transition period, correspond to an improper (older or newer) value.

Each element in the input array corresponds to a separate logical subscription change operation (although the operations may and will be executed together, if possible). This method allows for batch operations on monitored item subscriptions, potentially improving performance and efficiency when managing large numbers of subscriptions.

This member or type is for use from COM. It is not meant to be used from .NET or Python. Refer to the corresponding .NET member or type instead, if you are developing in .NET or Python.

Example

// This example shows how change the sampling rate of multiple existing monitored item subscriptions.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.


type
  TClientEventHandlers111 = class
    procedure OnDataChangeNotification(
      ASender: TObject;
      sender: OleVariant;
      const eventArgs: _EasyUADataChangeNotificationEventArgs);
  end;

procedure TClientEventHandlers111.OnDataChangeNotification(
  ASender: TObject;
  sender: OleVariant;
  const eventArgs: _EasyUADataChangeNotificationEventArgs);
begin
  // Display the data
  if eventArgs.Succeeded then
      WriteLn(eventArgs.Arguments.NodeDescriptor.ToString, ': ',
      eventArgs.AttributeData.ToString)
  else
      WriteLn(eventArgs.Arguments.NodeDescriptor.ToString, ' *** Failure: ',
      eventArgs.ErrorMessageBrief);
end;

class procedure ChangeMultipleMonitoredItemSubscriptions.Main;
var
  Arguments: OleVariant;
  Client: TEasyUAClient;
  ClientEventHandlers: TClientEventHandlers111;
  Handle: Cardinal;
  HandleArray: OleVariant;
  I: Cardinal;
  MonitoredItemArguments1, MonitoredItemArguments2, MonitoredItemArguments3:
    _EasyUAMonitoredItemArguments;
  OldMonitoringParameters, NewMonitoringParameters: _UAMonitoringParameters;
  SubscriptionChangeArguments: OleVariant;
  SubscriptionChangeArguments1, SubscriptionChangeArguments2, SubscriptionChangeArguments3:
    _EasyUASubscriptionChangeArguments;
begin
  // Instantiate the client object and hook events
  Client := TEasyUAClient.Create(nil);
  ClientEventHandlers := TClientEventHandlers111.Create;
  Client.OnDataChangeNotification := ClientEventHandlers.OnDataChangeNotification;

  WriteLn('Subscribing...');
  OldMonitoringParameters := CoUAMonitoringParameters.Create;
  OldMonitoringParameters.SamplingInterval := 1000;
  MonitoredItemArguments1 := CoEasyUAMonitoredItemArguments.Create;
  MonitoredItemArguments1.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  MonitoredItemArguments1.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10845';
  MonitoredItemArguments1.MonitoringParameters := OldMonitoringParameters;
  MonitoredItemArguments2 := CoEasyUAMonitoredItemArguments.Create;
  MonitoredItemArguments2.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  MonitoredItemArguments2.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10853';
  MonitoredItemArguments2.MonitoringParameters := OldMonitoringParameters;
  MonitoredItemArguments3 := CoEasyUAMonitoredItemArguments.Create;
  MonitoredItemArguments3.EndpointDescriptor.UrlString := 
    //'http://opcua.demo-this.com:51211/UA/SampleServer';
    //'https://opcua.demo-this.com:51212/UA/SampleServer/';
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer';
  MonitoredItemArguments3.NodeDescriptor.NodeId.ExpandedText := 'nsu=http://test.org/UA/Data/ ;i=10855';
  MonitoredItemArguments3.MonitoringParameters := OldMonitoringParameters;
  Arguments := VarArrayCreate([0, 2], varVariant);
  Arguments[0] := MonitoredItemArguments1;
  Arguments[1] := MonitoredItemArguments2;
  Arguments[2] := MonitoredItemArguments3;

  TVarData(HandleArray).VType := varArray or varVariant;
  TVarData(HandleArray).VArray := PVarArray(
    Client.SubscribeMultipleMonitoredItems(Arguments));

  for I := VarArrayLowBound(HandleArray, 1) to VarArrayHighBound(HandleArray, 1) do
  begin
      Handle := Cardinal(HandleArray[I]);
      WriteLn('HandleArray[', I, ']: ', Handle);
  end;

  WriteLn('Processing monitored item changed events for 10 seconds...');
  PumpSleep(10*1000);

  WriteLn('Changing subscriptions...');
  NewMonitoringParameters := CoUAMonitoringParameters.Create;
  NewMonitoringParameters.SamplingInterval := 100;
  SubscriptionChangeArguments1 := CoEasyUASubscriptionChangeArguments.Create;
  SubscriptionChangeArguments1.Handle := Cardinal(HandleArray[0]);
  SubscriptionChangeArguments1.MonitoringParameters := NewMonitoringParameters;
  SubscriptionChangeArguments2 := CoEasyUASubscriptionChangeArguments.Create;
  SubscriptionChangeArguments2.Handle := Cardinal(HandleArray[1]);
  SubscriptionChangeArguments2.MonitoringParameters := NewMonitoringParameters;
  SubscriptionChangeArguments3 := CoEasyUASubscriptionChangeArguments.Create;
  SubscriptionChangeArguments3.Handle := Cardinal(HandleArray[2]);
  SubscriptionChangeArguments3.MonitoringParameters := NewMonitoringParameters;
  SubscriptionChangeArguments := VarArrayCreate([0, 2], varVariant);
  SubscriptionChangeArguments[0] := SubscriptionChangeArguments1;
  SubscriptionChangeArguments[1] := SubscriptionChangeArguments2;
  SubscriptionChangeArguments[2] := SubscriptionChangeArguments3;

  Client.ChangeMultipleMonitoredItemSubscriptions(SubscriptionChangeArguments);

  WriteLn('Processing monitored item changed events for 10 seconds...');
  PumpSleep(10*1000);

  WriteLn('Unsubscribing...');
  Client.UnsubscribeAllMonitoredItems;

  WriteLn('Waiting for 5 seconds...');
  Sleep(5*1000);

  WriteLn('Finished.');
  VarClear(HandleArray);
  VarClear(Arguments);
  FreeAndNil(Client);
  FreeAndNil(ClientEventHandlers);
end;

Rem This example shows how change the sampling rate of multiple existing monitored item subscriptions.
Rem
Rem Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Rem OPC client and subscriber examples in VBScript on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBScript .
Rem Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
Rem a commercial license in order to use Online Forums, and we reply to every post.

' Instantiate the client object and hook events
Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.UA.EasyUAClient")
WScript.ConnectObject Client, "Client_"

WScript.Echo "Subscribing..."
Dim OldMonitoringParameters: Set OldMonitoringParameters = CreateObject("OpcLabs.EasyOpc.UA.UAMonitoringParameters")
OldMonitoringParameters.SamplingInterval = 1000
Dim MonitoredItemArguments1: Set MonitoredItemArguments1 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.EasyUAMonitoredItemArguments")
MonitoredItemArguments1.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
MonitoredItemArguments1.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10845"
MonitoredItemArguments1.MonitoringParameters = OldMonitoringParameters
Dim MonitoredItemArguments2: Set MonitoredItemArguments2 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.EasyUAMonitoredItemArguments")
MonitoredItemArguments2.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
MonitoredItemArguments2.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10853"
MonitoredItemArguments2.MonitoringParameters = OldMonitoringParameters
Dim MonitoredItemArguments3: Set MonitoredItemArguments3 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.EasyUAMonitoredItemArguments")
MonitoredItemArguments3.EndpointDescriptor.UrlString = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
MonitoredItemArguments3.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10855"
MonitoredItemArguments3.MonitoringParameters = OldMonitoringParameters
Dim arguments(2)
Set arguments(0) = MonitoredItemArguments1
Set arguments(1) = MonitoredItemArguments2
Set arguments(2) = MonitoredItemArguments3
Dim handleArray: handleArray = Client.SubscribeMultipleMonitoredItems(arguments)

Dim i: For i = LBound(handleArray) To UBound(handleArray)
    WScript.Echo "handleArray(" & i & "): " & handleArray(i)
Next

WScript.Echo "Processing monitored item changed events for 10 seconds..."
WScript.Sleep 10 * 1000

WScript.Echo "Changing subscriptions..."
Dim NewMonitoringParameters: Set NewMonitoringParameters = CreateObject("OpcLabs.EasyOpc.UA.UAMonitoringParameters")
NewMonitoringParameters.SamplingInterval = 100
Dim SubscriptionChangeArguments1: Set SubscriptionChangeArguments1 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.EasyUASubscriptionChangeArguments")
SubscriptionChangeArguments1.Handle = handleArray(0)
Set SubscriptionChangeArguments1.MonitoringParameters = NewMonitoringParameters
Dim SubscriptionChangeArguments2: Set SubscriptionChangeArguments2 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.EasyUASubscriptionChangeArguments")
SubscriptionChangeArguments2.Handle = handleArray(1)
Set SubscriptionChangeArguments2.MonitoringParameters = NewMonitoringParameters
Dim SubscriptionChangeArguments3: Set SubscriptionChangeArguments3 = CreateObject("OpcLabs.EasyOpc.UA.OperationModel.EasyUASubscriptionChangeArguments")
SubscriptionChangeArguments3.Handle = handleArray(2)
Set SubscriptionChangeArguments3.MonitoringParameters = NewMonitoringParameters
Dim subscriptionChangeArguments(2)
Set subscriptionChangeArguments(0) = SubscriptionChangeArguments1
Set subscriptionChangeArguments(1) = SubscriptionChangeArguments2
Set subscriptionChangeArguments(2) = SubscriptionChangeArguments3
Client.ChangeMultipleMonitoredItemSubscriptions subscriptionChangeArguments

WScript.Echo "Processing monitored item changed events for 10 seconds..."
WScript.Sleep 10 * 1000

WScript.Echo "Unsubscribing..."
Client.UnsubscribeAllMonitoredItems

WScript.Echo "Waiting for 5 seconds..."
WScript.Sleep 5 * 1000



Sub Client_DataChangeNotification(Sender, e)
    ' Display the data
    Dim display: If e.Exception Is Nothing Then display = e.AttributeData Else display = e.ErrorMessageBrief
    WScript.Echo e.Arguments.NodeDescriptor & ":" & display
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

_EasyUAClient Interface
_EasyUAClient Members
GetMonitoredItemArguments Method
GetMonitoredItemArgumentsDictionary Method
SubscribeMultipleMonitoredItems Method
UnsubscribeAllMonitoredItems Method
UnsubscribeMultipleMonitoredItems Method

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