Examples - OPC Data Access - Browse for nodes

.NET

// This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
// whether the node is a branch or a leaf.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// 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.

using System;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.AddressSpace;
using OpcLabs.EasyOpc.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class BrowseNodes
    {
        public static void Main1()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            DANodeElementCollection nodeElements;
            try
            {
                nodeElements = client.BrowseNodes("", "OPCLabs.KitServer.2", "Greenhouse", DABrowseParameters.Default);
            }
            catch (OpcException opcException)
            {
                Console.WriteLine($"*** Failure: {opcException.GetBaseException().Message}");
                return;
            }

            foreach (DANodeElement nodeElement in nodeElements)
            {
                Console.WriteLine($"NodeElements(\"{nodeElement.Name}\"):");
                Console.WriteLine($"    .IsBranch: {nodeElement.IsBranch}");
                Console.WriteLine($"    .IsLeaf: {nodeElement.IsLeaf}");
            }
        }
    }
}

# This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
# whether the node is a branch or a leaf.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in PowerShell on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PowerShell .
# 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.

#requires -Version 5.1
using namespace OpcLabs.EasyOpc.OperationModel
using namespace OpcLabs.EasyOpc.DataAccess

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

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

try {
    $nodeElements = [IEasyDAClientExtension]::BrowseNodes($client,
        "", "OPCLabs.KitServer.2", "Greenhouse", [DABrowseParameters]::Default)
}
catch [OpcException] {
    Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
    return
}

Foreach ($nodeElement in $nodeElements) {
    Write-Host "NodeElements(`"$($nodeElement.Name)`"):"
    Write-Host "    .IsBranch: $($nodeElement.IsBranch)"
    Write-Host "    .IsLeaf: $($nodeElement.IsLeaf)"
}

' This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
' whether the node is a branch or a leaf.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' 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.

Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.AddressSpace
Imports OpcLabs.EasyOpc.OperationModel

Namespace DataAccess._EasyDAClient
    Partial Friend Class BrowseNodes
        Shared Sub Main1()
            Dim client = New EasyDAClient()

            Dim nodeElements As DANodeElementCollection
            Try
                nodeElements = client.BrowseNodes("", "OPCLabs.KitServer.2", "Greenhouse", DABrowseParameters.Default)
            Catch opcException As OpcException
                Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
                Exit Sub
            End Try

            For Each nodeElement In nodeElements
                Console.WriteLine($"NodeElements(""{nodeElement.Name}""):")
                Console.WriteLine($"    .IsBranch: {nodeElement.IsBranch}")
                Console.WriteLine($"    .IsLeaf: {nodeElement.IsLeaf}")
            Next nodeElement

        End Sub
    End Class
End Namespace

COM

// This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
// whether the node is a branch or a leaf.
//
// 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.

class procedure BrowseNodes.Main;
var
  BrowseParameters: _DABrowseParameters;
  Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
  Count: Cardinal;
  Element: OleVariant;
  ServerDescriptor: _ServerDescriptor;
  NodeDescriptor: _DANodeDescriptor;
  NodeElement: _DANodeElement;
  NodeElementEnumerator: IEnumVariant;
  NodeElements: _DANodeElementCollection;
begin
  ServerDescriptor := CoServerDescriptor.Create;
  ServerDescriptor.ServerClass := 'OPCLabs.KitServer.2';

  NodeDescriptor := CoDANodeDescriptor.Create;
  NodeDescriptor.ItemId := 'Simulation';

  BrowseParameters := CoDABrowseParameters.Create;

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

  try
    NodeElements := Client.BrowseNodes(
      ServerDescriptor,
      NodeDescriptor,
      BrowseParameters);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  NodeElementEnumerator := NodeElements.GetEnumerator;
  while (NodeElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    NodeElement := IUnknown(Element) as _DANodeElement;
//    WriteLn(NodeElement.Name, ': ', NodeElement.ItemId);
    WriteLn('BrowseElements("', NodeElement.Name, '"):');
    WriteLn('    .IsBranch: ', NodeElement.IsBranch);
    WriteLn('    .IsLeaf: ', NodeElement.IsLeaf);
  end;
end;

// This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
// whether the node is a branch or a leaf.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in PHP on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PHP .
// 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.

$ServerDescriptor = new COM("OpcLabs.EasyOpc.ServerDescriptor");
$ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";

$NodeDescriptor = new COM("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor");
$NodeDescriptor->ItemID = "Simulation";

$BrowseParameters = new COM("OpcLabs.EasyOpc.DataAccess.DABrowseParameters");

$Client = new COM("OpcLabs.EasyOpc.DataAccess.EasyDAClient");

try
{
    $NodeElements = $Client->BrowseNodes($ServerDescriptor, $NodeDescriptor, $BrowseParameters);
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    Exit();
}

foreach ($NodeElements as $NodeElement)
{
    printf("NodeElements(\"%s\"):\n", $NodeElement->Name);
    printf("    .IsBranch: %s\n", $NodeElement->IsBranch ? 'true' : 'false');
    printf("    .IsLeaf: %s\n", $NodeElement->IsLeaf ? 'true' : 'false');
}

// This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
// whether the node is a branch or a leaf.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

mle_outputtext.Text = ""

// Instantiate the client object
OLEObject client
client = CREATE OLEObject
client.ConnectToNewObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")

// Prepare the arguments

OLEObject serverDescriptor
serverDescriptor = CREATE OLEObject
serverDescriptor.ConnectToNewObject("OpcLabs.EasyOpc.ServerDescriptor")
serverDescriptor.ServerClass = "OPCLabs.KitServer.2"

OLEObject nodeDescriptor
nodeDescriptor = CREATE OLEObject
nodeDescriptor.ConnectToNewObject("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor")
nodeDescriptor.ItemID = "Simulation"

OLEObject browseParameters
browseParameters = CREATE OLEObject
browseParameters.ConnectToNewObject("OpcLabs.EasyOpc.DataAccess.DABrowseParameters")

// Perform the operation
OLEObject nodeElements
TRY
    nodeElements = client.BrowseNodes(serverDescriptor, nodeDescriptor, browseParameters)
CATCH (OLERuntimeError oleRuntimeError)
    mle_outputtext.Text = mle_outputtext.Text + "*** Failure: " + oleRuntimeError.Description + "~r~n"
    RETURN
END TRY

OLEObject nodeElementList
nodeElementList = nodeElements.ToList()

// Display results
Int i
FOR i = 0 TO nodeElementList.Count - 1
    OLEObject nodeElement
    nodeElement = nodeElementList.Item[i]
    mle_outputtext.Text = mle_outputtext.Text + 'NodeElements("' + nodeElement.Name + '"):' + "~r~n" 
    mle_outputtext.Text = mle_outputtext.Text + "    nodeElement.IsBranch: " + String(nodeElement.IsBranch) + "~r~n"
    mle_outputtext.Text = mle_outputtext.Text + "    nodeElement.IsLeaf: " + String(nodeElement.IsLeaf) + "~r~n"
NEXT

mle_outputtext.Text = mle_outputtext.Text + "~r~n" 
mle_outputtext.Text = mle_outputtext.Text + "Finished." + "~r~n"

# This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
# whether the node is a branch or a leaf.
#
# 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!
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
import win32com.client
from pywintypes import com_error

serverDescriptor = win32com.client.Dispatch('OpcLabs.EasyOpc.ServerDescriptor')
serverDescriptor.ServerClass = 'OPCLabs.KitServer.2'

nodeDescriptor = win32com.client.Dispatch('OpcLabs.EasyOpc.DataAccess.DANodeDescriptor')
nodeDescriptor.ItemID = 'Simulation'

browseParameters = win32com.client.Dispatch('OpcLabs.EasyOpc.DataAccess.DABrowseParameters')

# Instantiate the client object
client = win32com.client.Dispatch('OpcLabs.EasyOpc.DataAccess.EasyDAClient') 

# Perform the operation
try:
    nodeElements = client.BrowseNodes(serverDescriptor, nodeDescriptor, browseParameters)
except com_error as e:
    print('*** Failure: ' + e.args[2][1] + ': ' + e.args[2][2])
    exit()

# Display results
for nodeElement in nodeElements:
    print('NodeElements("' + nodeElement.Name + '"):')
    print('    .IsBranch:', nodeElement.IsBranch)
    print('    .IsLeaf:', nodeElement.IsLeaf)


# Example output:
#
#NodeElements("Register_ArrayOfI1"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Register_ArrayOfI2"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Register_ArrayOfI4"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Staircase 0:2 (10 s)"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Constant_VARIANT"):
#    .IsBranch: False
#    .IsLeaf: True
#...

REM This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
REM whether the node is a branch or a leaf.
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 Visual Basic on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VB .
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.

Private Sub BrowseNodes_Main_Command_Click()
    OutputText = ""
    
    Dim serverDescriptor As New serverDescriptor
    serverDescriptor.ServerClass = "OPCLabs.KitServer.2"
    
    Dim nodeDescriptor As New DANodeDescriptor
    nodeDescriptor.itemId = "Simulation"
    
    Dim browseParameters As New DABrowseParameters
    
    ' Instantiate the client object
    Dim client As New EasyDAClient

    On Error Resume Next
    Dim nodeElements As DANodeElementCollection
    Set nodeElements = client.BrowseNodes(serverDescriptor, nodeDescriptor, browseParameters)
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0

    Dim nodeElement: For Each nodeElement In nodeElements
        OutputText = OutputText & "BrowseElements(""" & nodeElement.Name & """): " & nodeElement.itemId & vbCrLf
        OutputText = OutputText & "    .IsBranch: " & nodeElement.IsBranch & vbCrLf
        OutputText = OutputText & "    .IsLeaf: " & nodeElement.IsLeaf & vbCrLf
    Next
    
End Sub

Rem This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
Rem whether the node is a branch or a leaf.
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.

Option Explicit

Dim ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"

Dim NodeDescriptor: Set NodeDescriptor = CreateObject("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor")
NodeDescriptor.ItemID = "Simulation"

Dim BrowseParameters: Set BrowseParameters = CreateObject("OpcLabs.EasyOpc.DataAccess.DABrowseParameters")

Dim Client: Set Client= CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
On Error Resume Next
Dim NodeElements: Set NodeElements = Client.BrowseNodes(ServerDescriptor, NodeDescriptor, BrowseParameters)
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

Dim NodeElement: For Each NodeElement In NodeElements
    WScript.Echo "NodeElements(""" & NodeElement.Name & """):"
    With NodeElement
        WScript.Echo Space(4) & ".IsBranch: " & .IsBranch
        WScript.Echo Space(4) & ".IsLeaf: " & .IsLeaf
    End With
Next

Python

Python (.NET)

# This example shows how to obtain all nodes under the "Simulation" branch of the address space. For each node, it displays
# whether the node is a branch or a leaf.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# 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.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object
client = EasyDAClient()

# Perform the operation
try:
    nodeElements = IEasyDAClientExtension.BrowseNodes(client,
        '', 'OPCLabs.KitServer.2', 'Greenhouse', DABrowseParameters.Default)
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message)
    exit()

# Display results
for nodeElement in nodeElements:
    print('NodeElements("' + nodeElement.Name + '"):')
    print('    .IsBranch:', nodeElement.IsBranch)
    print('    .IsLeaf:', nodeElement.IsLeaf)


# Example output:
#
#NodeElements("Register_ArrayOfI1"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Register_ArrayOfI2"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Register_ArrayOfI4"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Staircase 0:2 (10 s)"):
#    .IsBranch: False
#    .IsLeaf: True
#NodeElements("Constant_VARIANT"):
#    .IsBranch: False
#    .IsLeaf: True
#...

Concepts

Browsing for OPC Classic Nodes (Branches and Leaves)

Examples - Client OPC Unified Architecture

Examples - OPC Unified Architecture - Browsing for data nodes