CallMethod(IEasyUAClient,UAEndpointDescriptor,UANodeDescriptor,UANodeDescriptor) Method

Calls (invokes) a method (or methods) in an OPC server. Input and output arguments can be passed to/from methods. Calls a method with no input arguments, using an endpoint descriptor and an object node Id.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<ElementsCanBeNullAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function CallMethod( _
   ByVal client As IEasyUAClient, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal objectNodeDescriptor As UANodeDescriptor, _
   ByVal methodNodeDescriptor As UANodeDescriptor _
) As Object()

'Usage
 
Dim client As IEasyUAClient
Dim endpointDescriptor As UAEndpointDescriptor
Dim objectNodeDescriptor As UANodeDescriptor
Dim methodNodeDescriptor As UANodeDescriptor
Dim value() As Object
 
value = IEasyUAClientExtension.CallMethod(client, endpointDescriptor, objectNodeDescriptor, methodNodeDescriptor)

[Extension()]
[ElementsCanBeNull()]
[NotNull()]
public static object[] CallMethod( 
   IEasyUAClient client,
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor objectNodeDescriptor,
   UANodeDescriptor methodNodeDescriptor
)

[Extension()]
[ElementsCanBeNull()]
[NotNull()]
public:
static array<Object^>^ CallMethod( 
   IEasyUAClient^ client,
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ objectNodeDescriptor,
   UANodeDescriptor^ methodNodeDescriptor
)

Parameters

client: The client object that will perform the operation.
endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
objectNodeDescriptor: Node descriptor. Identifies the node in OPC server's address space.
methodNodeDescriptor: Method Node Id. Identifies the method node in OPC server's address space.

Return Value

Array of output arguments from the method call. The number of arguments and their types are given by the method.

Exceptions

Exception Description

Exception	Description
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.
OpcLabs.EasyOpc.UA.OperationModel.UAException	The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause. This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

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.

OpcLabs.EasyOpc.UA.OperationModel.UAException

The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

If you want to call methods that are defined in the OPC UA specifications or OPC UA companion specifications, consider first whether extension methods or specialized client objects exist for the purpose, because using them is much easier. For example, in order to call methods provided by OPC UA Global Discovery Server (GDS), you should rather use the OpcLabs.EasyOpc.UA.Gds.EasyUAGlobalDiscoveryClientCore or the OpcLabs.EasyOpc.UA.Gds.EasyUACertificateManagementClientCore object, or use the methods provided by the OpcLabs.EasyOpc.UA.Application.IEasyUAClientServerApplication service.

Example

// This example shows how to call a single method, and pass arguments to and from it.

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

namespace UADocExamples._EasyUAClient
{
    class CallMethod
    {
        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/"

            object[] inputs =
            {
                false, 
                1, 
                2, 
                3, 
                4, 
                5, 
                6, 
                7, 
                8, 
                9, 
                10
            };

            TypeCode[] typeCodes =
            {
                TypeCode.Boolean,
                TypeCode.SByte,
                TypeCode.Byte,
                TypeCode.Int16,
                TypeCode.UInt16,
                TypeCode.Int32,
                TypeCode.UInt32,
                TypeCode.Int64,
                TypeCode.UInt64,
                TypeCode.Single,
                TypeCode.Double
            };

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

            // Perform the operation.
            object[] outputs;
            try
            {
                outputs = client.CallMethod(
                    endpointDescriptor,
                    "nsu=http://test.org/UA/Data/ ;i=10755",
                    "nsu=http://test.org/UA/Data/ ;i=10756",
                    inputs,
                    typeCodes);
            }
            catch (UAException uaException)
            {
                Console.WriteLine($"*** Failure: {uaException.GetBaseException().Message}");
                return;
            }

            // Display results
            for (int i = 0; i < outputs.Length; i++)
                Console.WriteLine($"outputs[{i}]: {outputs[i]}");

            // Example output:
            //outputs[0]: False
            //outputs[1]: 1
            //outputs[2]: 2
            //outputs[3]: 3
            //outputs[4]: 4
            //outputs[5]: 5
            //outputs[6]: 6
            //outputs[7]: 7
            //outputs[8]: 8
            //outputs[9]: 9
            //outputs[10]: 10        
        }
    }
}

# This example shows how to call a single method, and pass arguments to and from it.

#requires -Version 5.1
using namespace System
using namespace OpcLabs.EasyOpc.UA
using namespace OpcLabs.EasyOpc.UA.OperationModel

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUA.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUAComponents.dll"

[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/"

$inputs = @(
    $false,
    1, 
    2, 
    3, 
    4, 
    5, 
    6, 
    7, 
    8, 
    9, 
    10)

$typeCodes = @(
    [TypeCode]::Boolean,
    [TypeCode]::SByte,
    [TypeCode]::Byte,
    [TypeCode]::Int16,
    [TypeCode]::UInt16,
    [TypeCode]::Int32,
    [TypeCode]::UInt32,
    [TypeCode]::Int64,
    [TypeCode]::UInt64,
    [TypeCode]::Single,
    [TypeCode]::Double)

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

# Perform the operation.
try {
    $outputs = $client.CallMethod(
                    $endpointDescriptor,
                    "nsu=http://test.org/UA/Data/ ;i=10755",
                    "nsu=http://test.org/UA/Data/ ;i=10756",
                    $inputs,
                    $typeCodes)
}
catch [UAException] {
    Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
    return
}

# Display results
for ($i = 0; $i -lt $outputs.Length; $i++) {
    Write-Host "outputs[$($i)]: $($outputs[$i])"
}


# Example output:
#
#outputs[0]: False
#outputs[1]: 1
#outputs[2]: 2
#outputs[3]: 3
#outputs[4]: 4
#outputs[5]: 5
#outputs[6]: 6
#outputs[7]: 7
#outputs[8]: 8
#outputs[9]: 9
#outputs[10]: 10

# This example shows how to call a single method, and pass arguments to and from it.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.OperationModel import *


endpointDescriptor = UAEndpointDescriptor('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/'

# 
inputs = [False, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
typeCodes = [
    TypeCode.Boolean,
    TypeCode.SByte,
    TypeCode.Byte,
    TypeCode.Int16,
    TypeCode.UInt16,
    TypeCode.Int32,
    TypeCode.UInt32,
    TypeCode.Int64,
    TypeCode.UInt64,
    TypeCode.Single,
    TypeCode.Double,
    ]

# Instantiate the client object.
client = EasyUAClient()

# Perform the operation.
try:
    outputs = IEasyUAClientExtension.CallMethod(client,
        endpointDescriptor,
        UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10755'),
        UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10756'),
        inputs,
        typeCodes)
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

# Display results.
for i, value in enumerate(outputs):
     print('outputs[', i, ']: ', value, sep='')


# Example output:
#outputs[0]: False
#outputs[1]: 1
#outputs[2]: 2
#outputs[3]: 3
#outputs[4]: 4
#outputs[5]: 5
#outputs[6]: 6
#outputs[7]: 7
#outputs[8]: 8
#outputs[9]: 9.0
#outputs[10]: 10.0

' This example shows how to call a single method, and pass arguments to and from it.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Friend Class CallMethod
        Public Shared Sub Main1()

            Dim endpointDescriptor As UAEndpointDescriptor =
                "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/"

            Dim inputs() As Object =
            { _
                False,
                1,
                2,
                3,
                4,
                5,
                6,
                7,
                8,
                9,
                10
            }

            Dim typeCodes() As TypeCode =
            { _
                TypeCode.Boolean,
                TypeCode.SByte,
                TypeCode.Byte,
                TypeCode.Int16,
                TypeCode.UInt16,
                TypeCode.Int32,
                TypeCode.UInt32,
                TypeCode.Int64,
                TypeCode.UInt64,
                TypeCode.Single,
                TypeCode.Double
            }

            ' Instantiate the client object
            Dim client = New EasyUAClient()

            ' Perform the operation
            Dim outputs() As Object
            Try
                outputs = client.CallMethod( _
                    endpointDescriptor, _
                    "nsu=http://test.org/UA/Data/ ;i=10755", _
                    "nsu=http://test.org/UA/Data/ ;i=10756", _
                    inputs, _
                    typeCodes)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display results
            For i As Integer = 0 To outputs.Length - 1
                Console.WriteLine("outputs[{0}]: {1}", i, outputs(i))
            Next i

            ' Example output:
            'outputs[0]: False
            'outputs[1]: 1
            'outputs[2]: 2
            'outputs[3]: 3
            'outputs[4]: 4
            'outputs[5]: 5
            'outputs[6]: 6
            'outputs[7]: 7
            'outputs[8]: 8
            'outputs[9]: 9
            'outputs[10]: 10        
        End Sub
    End Class
End Namespace

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

IEasyUAClientExtension Class
IEasyUAClientExtension Members
Overload List

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