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.

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.

#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.

# 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
#...

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.

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.

$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.

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!
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.

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.

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

Conceptual

Browsing for OPC Classic Nodes (Branches and Leaves)

Examples - OPC Unified Architecture

Examples - OPC Unified Architecture - Browsing for data nodes