OPC Studio User's Guide and Reference
WriteMultipleValues Method (_EasyUAClient)
Example 



View with Navigation Tools
OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.ComTypes Namespace > _EasyUAClient Interface : WriteMultipleValues Method
Array of OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments. Array of argument objects specifying what to write from an OPC-UA server.
Writes values into multiple attributes, using array of argument objects as an input (status codes and timestamps are not written).
Syntax
'Declaration
 
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Function WriteMultipleValues( _
   ByVal writeValueArgumentsArray As Object _
) As Object()
 
'Usage
 
Dim instance As _EasyUAClient
Dim writeValueArgumentsArray As Object
Dim value() As Object
 
value = instance.WriteMultipleValues(writeValueArgumentsArray)

Parameters

writeValueArgumentsArray
Array of OpcLabs.EasyOpc.UA.OperationModel.UAWriteValueArguments. Array of argument objects specifying what to write from an OPC-UA server.

Return Value

Array of OpcLabs.EasyOpc.UA.OperationModel.UAWriteResult. The method returns an array of OpcLabs.EasyOpc.UA.OperationModel.UAWriteResult objects. The indices of elements in the output array are the same as those in the input arrays.
Exceptions
ExceptionDescription

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 size of the input array will become the size of the output array. The element positions (indices) in the output array are the same as in the input array.

This method does not throw an exception in case of OPC operation failures. Instead, the eventual exception related to each item is returned in Exception property of each returned OpcLabs.EasyOpc.UA.OperationModel.UAWriteResult element.

 

This is a multiple-operation method. In a properly written program, it does not throw any exceptions. You should therefore not put try/catch statements or similar constructs around calls to this method. The only exceptions thrown by this method are for usage errors, i.e. when your code violates the usage contract of the method, such as passing in invalid arguments or calling the method when the state of the object does not allow it. Any operation-related errors (i.e. errors that depend on external conditions that your code cannot reliably check) are indicated in the result objects returned by the method. For more information, see Multiple-operation Methods and Do not catch any exceptions with asynchronous or multiple-operation methods.
Example

.NET

.NET

COM

// This example shows how to write values into 3 nodes at once.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    partial class WriteMultipleValues
    {
        public static void Main1()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            // Instantiate the client object
            var client = new EasyUAClient();

            // Modify value of a node
            client.WriteMultipleValues(new[]
                {
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 2.34567890),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10227", "ABC")
                });
            // Production code would check the success of the operation. See separate example for that.
        }
    }
}
// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
// message in case of failure.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.BaseLib.OperationModel;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    partial class WriteMultipleValues
    {
        public static void TestSuccess()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"
            
            // Instantiate the client object.
            var client = new EasyUAClient();

            Console.WriteLine("Modifying values of nodes...");
            OperationResult[] operationResultArray = client.WriteMultipleValues(new[]
                {
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 
                        "This string cannot be converted to Double"),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC")
                });

            for (int i = 0; i < operationResultArray.Length; i++)
                if (operationResultArray[i].Succeeded)
                    Console.WriteLine($"Result {i}: success");
                else
                    Console.WriteLine($"Result {i}: {operationResultArray[i].Exception.GetBaseException().Message}");


            // Example output:
            //
            //Modifying values of nodes...
            //Result 0: success
            //Result 1: Input string was not in a correct format.
            //+ Attempting to change an object of type "System.String" to type "System.Double".
            //+ The specified original value (string) was "This string cannot be converted to Double".
            //+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;i=10226".
            //+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
            //Result 2: The status of the OPC-UA attribute data is not Good. The actual status is 'BadNodeIdUnknown'.
            //+ During writing or method calls, readings may occur when value type is not specified.
            //+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;s=UnknownNode".
            //+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
        }
    }
}
// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception
// message in case of failure.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

#include "stdafx.h"    // Includes "QuickOpc.h", and other commonly used files
#include <atlsafe.h>
#include "WriteMultipleValues.h"

namespace _EasyUAClient
{
    void WriteMultipleValues::TestSuccess()
    {
        // Initialize the COM library
        CoInitializeEx(NULL, COINIT_MULTITHREADED);
        {
            // Instantiate the client object
            _EasyUAClientPtr ClientPtr(__uuidof(EasyUAClient));

            _UAWriteValueArgumentsPtr WriteValueArguments1Ptr(_uuidof(UAWriteValueArguments));
            WriteValueArguments1Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            WriteValueArguments1Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10221";
            WriteValueArguments1Ptr->Value = 23456;

            _UAWriteValueArgumentsPtr WriteValueArguments2Ptr(_uuidof(UAWriteValueArguments));
            WriteValueArguments2Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            WriteValueArguments2Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;i=10226";
            WriteValueArguments2Ptr->Value = L"This string cannot be converted to Double";

            _UAWriteValueArgumentsPtr WriteValueArguments3Ptr(_uuidof(UAWriteValueArguments));
            WriteValueArguments3Ptr->EndpointDescriptor->UrlString = 
                //L"http://opcua.demo-this.com:51211/UA/SampleServer";
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            WriteValueArguments3Ptr->NodeDescriptor->NodeId->ExpandedText = L"nsu=http://test.org/UA/Data/ ;s=UnknownNode";
            WriteValueArguments3Ptr->Value = L"ABC";

            CComSafeArray<VARIANT> arguments(3);
            arguments.SetAt(0, _variant_t((IDispatch*)WriteValueArguments1Ptr));
            arguments.SetAt(1, _variant_t((IDispatch*)WriteValueArguments2Ptr));
            arguments.SetAt(2, _variant_t((IDispatch*)WriteValueArguments3Ptr));
            CComVariant vArguments(arguments);

            // Obtain values. By default, the Value attributes of the nodes will be Write.
            CComSafeArray<VARIANT> results;
            results.Attach(ClientPtr->WriteMultipleValues(&vArguments));
            
            // Display results
            for (int i = results.GetLowerBound(); i <= results.GetUpperBound(); i++)
            {
                _UAWriteResultPtr ResultPtr = results[i];

                if (ResultPtr->Succeeded)
                    _tprintf(_T("Result %d success\n"), i);
                else
                    _tprintf(_T("Result  s\n"), i, (LPCTSTR)CW2CT(ResultPtr->Exception->GetBaseException()->Message));
            }
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}
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