QuickOPC User's Guide and Reference
CallMethod Method (_EasyUAClient)
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.ComTypes Namespace > _EasyUAClient Interface : CallMethod Method
Endpoint descriptor. Identifies the OPC-UA server.
Node descriptor. Identifies the node in OPC server's address space.
Method Node Id. Identifies the method node in OPC server's address space.
Array of input arguments to the method call.
Array of System.Int32, representing System.TypeCode values. The types that should be used when passing the input arguments to the server. The number of arguments and their types must conform to the method's requirements.
Calls a method with specified input arguments, using an endpoint descriptor and an object node Id.
Syntax
'Declaration
 

<ElementsCanBeNullAttribute()>
<NotNullAttribute()>
Function CallMethod( _
   ByVal endpointDescriptorString As String, _
   ByVal objectNodeDescriptorString As String, _
   ByVal methodNodeDescriptorString As String, _
   ByVal inputArguments As Object, _
   ByVal inputTypeCodes As Object _
) As Object()
'Usage
 

Dim instance As _EasyUAClient
Dim endpointDescriptorString As String
Dim objectNodeDescriptorString As String
Dim methodNodeDescriptorString As String
Dim inputArguments As Object
Dim inputTypeCodes As Object
Dim value() As Object
 
value = instance.CallMethod(endpointDescriptorString, objectNodeDescriptorString, methodNodeDescriptorString, inputArguments, inputTypeCodes)
[ElementsCanBeNull()]
[NotNull()]
object[] CallMethod( 
   string endpointDescriptorString,
   string objectNodeDescriptorString,
   string methodNodeDescriptorString,
   object inputArguments,
   object inputTypeCodes
)
[ElementsCanBeNull()]
[NotNull()]
array<Object^>^ CallMethod( 
   String^ endpointDescriptorString,
   String^ objectNodeDescriptorString,
   String^ methodNodeDescriptorString,
   Object^ inputArguments,
   Object^ inputTypeCodes
)

Parameters

endpointDescriptorString
Endpoint descriptor. Identifies the OPC-UA server.
objectNodeDescriptorString
Node descriptor. Identifies the node in OPC server's address space.
methodNodeDescriptorString
Method Node Id. Identifies the method node in OPC server's address space.
inputArguments
Array of input arguments to the method call.
inputTypeCodes
Array of System.Int32, representing System.TypeCode values. The types that should be used when passing the input arguments to the server. The number of arguments and their types must conform to the method's requirements.

Return Value

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

Hint for VB6, VBA and VBScript users: If you need to call an OPC UA method with no input arguments, use the Array() function, with no argument, to create an empty array. Alternatively, create an (empty) OpcLabs.BaseLib.Collections.ElasticVector, and convert it to an array using its OpcLabs.BaseLib.Collections.ElasticVector.ToArray Method.

Example

COM

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

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

namespace _EasyUAClient
{
    void CallMethod::Main()
    {
        // Initialize the COM library
        CoInitializeEx(NULL, COINIT_MULTITHREADED);
        {
            CComSafeArray<VARIANT> inputs(11);
            inputs.SetAt(0, _variant_t(false));
            inputs.SetAt(1, _variant_t(1));
            inputs.SetAt(2, _variant_t(2));
            inputs.SetAt(3, _variant_t(3));
            inputs.SetAt(4, _variant_t(4));
            inputs.SetAt(5, _variant_t(5));
            inputs.SetAt(6, _variant_t(6));
            inputs.SetAt(7, _variant_t(7));
            inputs.SetAt(8, _variant_t(8));
            inputs.SetAt(9, _variant_t(9));
            inputs.SetAt(10, _variant_t(10));
            CComVariant vInputs(inputs);

            CComSafeArray<VARIANT> typeCodes(11);
            typeCodes.SetAt(0, _variant_t(TypeCode_Boolean));
            typeCodes.SetAt(1, _variant_t(TypeCode_SByte));
            typeCodes.SetAt(2, _variant_t(TypeCode_Byte));
            typeCodes.SetAt(3, _variant_t(TypeCode_Int16));
            typeCodes.SetAt(4, _variant_t(TypeCode_UInt16));
            typeCodes.SetAt(5, _variant_t(TypeCode_Int32));
            typeCodes.SetAt(6, _variant_t(TypeCode_UInt32));
            typeCodes.SetAt(7, _variant_t(TypeCode_Int64));
            typeCodes.SetAt(8, _variant_t(TypeCode_UInt64));
            typeCodes.SetAt(9, _variant_t(TypeCode_Single));
            typeCodes.SetAt(10, _variant_t(TypeCode_Double));
            CComVariant vTypeCodes(typeCodes);

            // Instantiate the client object
            _EasyUAClientPtr ClientPtr(__uuidof(EasyUAClient));

            // Perform the operation
            CComSafeArray<VARIANT> outputs;
            outputs.Attach(ClientPtr->CallMethod(
                //L"http://opcua.demo-this.com:51211/UA/SampleServer",
                L"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer",
                L"nsu=http://test.org/UA/Data/ ;i=10755",
                L"nsu=http://test.org/UA/Data/ ;i=10756",
                &vInputs,
                &vTypeCodes));
    
            // Display results
            for (int i = outputs.GetLowerBound(); i <= outputs.GetUpperBound(); i++)
            {
                _variant_t output(outputs[i]);
                _variant_t vString;
                vString.ChangeType(VT_BSTR, &output);
                _tprintf(_T("outputs(d)s\n"), i, (LPCTSTR)CW2CT((_bstr_t)vString));
            }
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

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

class procedure CallMethod.Main;
var
  Client: EasyUAClient;
  I: Cardinal;
  Inputs: OleVariant;
  Outputs: OleVariant;
  TypeCodes: OleVariant;
begin
  Inputs := VarArrayCreate([0, 10], varVariant);
  Inputs[0] := False;
  Inputs[1] := 1;
  Inputs[2] := 2;
  Inputs[3] := 3;
  Inputs[4] := 4;
  Inputs[5] := 5;
  Inputs[6] := 6;
  Inputs[7] := 7;
  Inputs[8] := 8;
  Inputs[9] := 9;
  Inputs[10] := 10;

  TypeCodes := VarArrayCreate([0, 10], varVariant);
  TypeCodes[0] := TypeCode_Boolean;
  TypeCodes[1] := TypeCode_SByte;
  TypeCodes[2] := TypeCode_Byte;
  TypeCodes[3] := TypeCode_Int16;
  TypeCodes[4] := TypeCode_UInt16;
  TypeCodes[5] := TypeCode_Int32;
  TypeCodes[6] := TypeCode_UInt32;
  TypeCodes[7] := TypeCode_Int64;
  TypeCodes[8] := TypeCode_UInt64;
  TypeCodes[9] := TypeCode_Single;
  TypeCodes[10] := TypeCode_Double;

  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Perform the operation
  TVarData(Outputs).VType := varArray or varVariant;
  TVarData(Outputs).VArray := PVarArray(Client.CallMethod(
    //'http://opcua.demo-this.com:51211/UA/SampleServer',
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer',
    'nsu=http://test.org/UA/Data/ ;i=10755',
    'nsu=http://test.org/UA/Data/ ;i=10756',
    PSafeArray(TVarData(Inputs).VArray),
    PSafeArray(TVarData(TypeCodes).VArray)));

  // Display results
  for I := VarArrayLowBound(Outputs, 1) to VarArrayHighBound(Outputs, 1) do
      try
        WriteLn('outputs(', I, '): ', Outputs[I]);
      except
        on EVariantError do WriteLn('*** Error displaying the value');
      end;
end;
// This example shows how to call a single method, and pass arguments to and
// from it.

class procedure CallMethod.Main;
var
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  I: Cardinal;
  Inputs: OleVariant;
  Outputs: OleVariant;
  TypeCodes: OleVariant;
begin
  Inputs := VarArrayCreate([0, 10], varVariant);
  Inputs[0] := False;
  Inputs[1] := 1;
  Inputs[2] := 2;
  Inputs[3] := 3;
  Inputs[4] := 4;
  Inputs[5] := 5;
  Inputs[6] := 6;
  Inputs[7] := 7;
  Inputs[8] := 8;
  Inputs[9] := 9;
  Inputs[10] := 10;

  TypeCodes := VarArrayCreate([0, 10], varVariant);
  TypeCodes[0] := TypeCode_Boolean;
  TypeCodes[1] := TypeCode_SByte;
  TypeCodes[2] := TypeCode_Byte;
  TypeCodes[3] := TypeCode_Int16;
  TypeCodes[4] := TypeCode_UInt16;
  TypeCodes[5] := TypeCode_Int32;
  TypeCodes[6] := TypeCode_UInt32;
  TypeCodes[7] := TypeCode_Int64;
  TypeCodes[8] := TypeCode_UInt64;
  TypeCodes[9] := TypeCode_Single;
  TypeCodes[10] := TypeCode_Double;

  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Perform the operation
  try
    TVarData(Outputs).VType := varArray or varVariant;
    TVarData(Outputs).VArray := PVarArray(Client.CallMethod(
      //'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',
      'nsu=http://test.org/UA/Data/ ;i=10755',
      'nsu=http://test.org/UA/Data/ ;i=10756',
      Inputs,
      TypeCodes));
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  // Display results
  for I := VarArrayLowBound(Outputs, 1) to VarArrayHighBound(Outputs, 1) do
      WriteLn('outputs(', I, '): ', Outputs[I]);

   VarClear(Outputs);
   VarClear(TypeCodes);
   VarClear(Inputs);

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

$inputs[0] = false;
$inputs[1] = 1;
$inputs[2] = 2;
$inputs[3] = 3;
$inputs[4] = 4;
$inputs[5] = 5;
$inputs[6] = 6;
$inputs[7] = 7;
$inputs[8] = 8;
$inputs[9] = 9;
$inputs[10] = 10;

$typeCodes[0] = 3;    // TypeCode.Boolean
$typeCodes[1] = 5;    // TypeCode.SByte
$typeCodes[2] = 6;    // TypeCode.Byte
$typeCodes[3] = 7;    // TypeCode.Int16
$typeCodes[4] = 8;    // TypeCode.UInt16
$typeCodes[5] = 9;    // TypeCode.Int32
$typeCodes[6] = 10;   // TypeCode.UInt32
$typeCodes[7] = 11;   // TypeCode.Int64
$typeCodes[8] = 12;   // TypeCode.UInt64
$typeCodes[9] = 13;   // TypeCode.Single
$typeCodes[10] = 14;  // TypeCode.Double

// Instantiate the client object
$Client = new COM("OpcLabs.EasyOpc.UA.EasyUAClient");

// Perform the operation
try
{
    $outputs = $Client->CallMethod(
        //"http://opcua.demo-this.com:51211/UA/SampleServer", 
        "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", 
        "nsu=http://test.org/UA/Data/ ;i=10755", 
        "nsu=http://test.org/UA/Data/ ;i=10756", 
        $inputs, 
        $typeCodes);
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    Exit();
}

// Display results
for ($i = 0; $i < count($outputs); $i++)
{
    printf("outputs[d]s\n", $i, $outputs[$i]);
}

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

# The Python for Windows (pywin32) extensions package is needed. Install it using "pip install pypiwin32".
# CAUTION: We now recommend using Python.NET package instead. Full set of examples with Python.NET is available!
import win32com.client
from pywintypes import com_error

# Instantiate the client object
client = win32com.client.Dispatch('OpcLabs.EasyOpc.UA.EasyUAClient') 

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


# Perform the operation
try:
    outputs = client.CallMethod(
        'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer',
        'nsu=http://test.org/UA/Data/ ;i=10755',
        'nsu=http://test.org/UA/Data/ ;i=10756',
        inputs,
        typeCodes)
    # outputs[0] contains the actual results; outputs[1] and outputs[2] are copies of inputs and typeCodes.
except com_error as e:
    print('*** Failure: ' + e.args[2][1] + ': ' + e.args[2][2])
    exit()


# Display results
for i, value in enumerate(outputs[0]):
     print('outputs[', i, ']: ', value)

# 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

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

Public Sub CallMethod_Main_Command_Click()
    OutputText = ""

    Dim inputs(10)
    inputs(0) = False
    inputs(1) = 1
    inputs(2) = 2
    inputs(3) = 3
    inputs(4) = 4
    inputs(5) = 5
    inputs(6) = 6
    inputs(7) = 7
    inputs(8) = 8
    inputs(9) = 9
    inputs(10) = 10

    Dim typeCodes(10)
    typeCodes(0) = 3    ' TypeCode.Boolean
    typeCodes(1) = 5    ' TypeCode.SByte
    typeCodes(2) = 6    ' TypeCode.Byte
    typeCodes(3) = 7    ' TypeCode.Int16
    typeCodes(4) = 8    ' TypeCode.UInt16
    typeCodes(5) = 9    ' TypeCode.Int32
    typeCodes(6) = 10   ' TypeCode.UInt32
    typeCodes(7) = 11   ' TypeCode.Int64
    typeCodes(8) = 12   ' TypeCode.UInt64
    typeCodes(9) = 13   ' TypeCode.Single
    typeCodes(10) = 14  ' TypeCode.Double

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    ' Perform the operation
    On Error Resume Next
    Dim outputs As Variant
    outputs = Client.CallMethod( _
        "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", _
        "nsu=http://test.org/UA/Data/ ;i=10755", _
        "nsu=http://test.org/UA/Data/ ;i=10756", _
        inputs, _
        typeCodes)
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0

    ' Display results
    Dim i: For i = LBound(outputs) To UBound(outputs)
        On Error Resume Next
        OutputText = OutputText & "outputs(" & i & "): " & outputs(i) & vbCrLf
        If Err <> 0 Then OutputText = OutputText & "*** Error" & vbCrLf ' occurrs with types not recognized by VB6
        On Error GoTo 0
    Next
End Sub
Rem This example shows how to call a single method, and pass arguments to and from it.

Option Explicit

Dim inputs(10)
inputs(0) = False
inputs(1) = 1
inputs(2) = 2
inputs(3) = 3
inputs(4) = 4
inputs(5) = 5
inputs(6) = 6
inputs(7) = 7
inputs(8) = 8
inputs(9) = 9
inputs(10) = 10

Dim typeCodes(10)
typeCodes(0) = 3    ' TypeCode.Boolean
typeCodes(1) = 5    ' TypeCode.SByte
typeCodes(2) = 6    ' TypeCode.Byte
typeCodes(3) = 7    ' TypeCode.Int16
typeCodes(4) = 8    ' TypeCode.UInt16
typeCodes(5) = 9    ' TypeCode.Int32
typeCodes(6) = 10   ' TypeCode.UInt32
typeCodes(7) = 11   ' TypeCode.Int64
typeCodes(8) = 12   ' TypeCode.UInt64
typeCodes(9) = 13   ' TypeCode.Single
typeCodes(10) = 14  ' TypeCode.Double

' Instantiate the client object
Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.UA.EasyUAClient")

' Perform the operation
On Error Resume Next
Dim outputs: outputs = Client.CallMethod( _
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", _
    "nsu=http://test.org/UA/Data/ ;i=10755", _
    "nsu=http://test.org/UA/Data/ ;i=10756", _
    inputs, _
    typeCodes)
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

' Display results
Dim i: For i = LBound(outputs) To UBound(outputs)
    On Error Resume Next
    WScript.Echo "outputs(" & i & "): " & outputs(i)
    If Err <> 0 Then WScript.Echo "*** Error"   ' occurrs with types not recognized by VBScript
    On Error Goto 0
Next
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

Reference

_EasyUAClient Interface
_EasyUAClient Members

 

 

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