BrowseDataNodes Method (

Browses the data nodes, specifying an endpoint descriptor, and a starting Node Id.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<NotNullAttribute()>
Function BrowseDataNodes( _
   ByVal endpointDescriptorString As String, _
   ByVal nodeDescriptorString As String _
) As UANodeElementCollection

'Usage
 
Dim instance As _EasyUAClient
Dim endpointDescriptorString As String
Dim nodeDescriptorString As String
Dim value As UANodeElementCollection
 
value = instance.BrowseDataNodes(endpointDescriptorString, nodeDescriptorString)

[NotNull()]
UANodeElementCollection BrowseDataNodes( 
   string endpointDescriptorString,
   string nodeDescriptorString
)

[NotNull()]
UANodeElementCollection^ BrowseDataNodes( 
   String^ endpointDescriptorString,
   String^ nodeDescriptorString
)

Parameters

endpointDescriptorString

Endpoint descriptor. Identifies the OPC-UA server.

The value represents an OPC UA endpoint descriptor string. Any string can be passed to this parameter (i.e. will not cause System.ArgumentException), but not all values make sense and will work when an operation using them is attempted. The OPC UA endpoint descriptor string is typically the URL of the server endpoint.

The value of this parameter can be null (Nothing in Visual Basic).

nodeDescriptorString

Node Id.

The value of this parameter can be null (Nothing in Visual Basic).

Return Value

The method returns a node element collection, which contains OpcLabs.EasyOpc.UA.AddressSpace.UANodeElement values. Each element contains information about a particular node found.

This method never returns null (Nothing in Visual Basic).

The individual elements of the returned value are never null (Nothing in Visual Basic).

Remarks

Data nodes are Objects and Variables (Variables are Data Variables and Properties).

This member or type is for use from COM. It is not meant to be used from .NET or Python. Refer to the corresponding .NET member or type instead, if you are developing in .NET or Python.

Example

// This example shows how to obtain all data nodes (objects and variables) under a given node of the OPC-UA address space.
// For each node, it displays its browse name and node ID.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// 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.

#include "stdafx.h"    // Includes "QuickOpc.h", and other commonly used files
#include "BrowseDataNodes.h"

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

            // Perform the operation
            _UANodeElementCollectionPtr NodeElementsPtr = ClientPtr->BrowseDataNodes(
                //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=10791");
    
            // Display results
            IEnumVARIANTPtr EnumNodeElementPtr = NodeElementsPtr->GetEnumerator();
            _variant_t vNodeElement;
            while (EnumNodeElementPtr->Next(1, &vNodeElement, NULL) == S_OK)
            {
                _UANodeElementPtr NodeElementPtr(vNodeElement);
                _tprintf(_T("%s: "), (LPCTSTR)CW2CT(NodeElementPtr->BrowseName->ToString));
                _tprintf(_T("%s\n"), (LPCTSTR)CW2CT(NodeElementPtr->NodeId->ToString));
                vNodeElement.Clear();
            }
        }
         // Release all interface pointers BEFORE calling CoUninitialize()
        CoUninitialize();
    }
}

// This example shows how to obtain all data nodes (objects and variables)
// under a given node of the OPC-UA address space. For each node, it displays
// its browse name and node ID.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// 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 BrowseDataNodes.Main;
var
  Client: EasyUAClient;
  Count: Cardinal;
  Element: OleVariant;
  NodeElement: _UANodeElement;
  NodeElementEnumerator: IEnumVariant;
  NodeElements: _UANodeElementCollection;
begin
  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  NodeElements := Client.BrowseDataNodes(
    //'http://opcua.demo-this.com:51211/UA/SampleServer',
    'opc.tcp://opcua.demo-this.com:51210/UA/SampleServer',
    'nsu=http://test.org/UA/Data/ ;i=10791');

  NodeElementEnumerator := NodeElements.GetEnumerator;
  while (NodeElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    NodeElement := IUnknown(Element) as _UANodeElement;
    WriteLn(NodeElement.BrowseName.ToString, ': ', NodeElement.NodeId.ToString);
  end;
end;

// This example shows how to obtain all data nodes (objects and variables)
// under a given node of the OPC-UA address space. For each node, it displays
// its browse name and node ID.
//
// 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 BrowseDataNodes.Main;
var
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  Count: Cardinal;
  Element: OleVariant;
  NodeElement: _UANodeElement;
  NodeElementEnumerator: IEnumVariant;
  NodeElements: _UANodeElementCollection;
begin
  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  try
    NodeElements := Client.BrowseDataNodes(
      //'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=10791');
  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 _UANodeElement;
    WriteLn(NodeElement.BrowseName.ToString, ': ', NodeElement.NodeId.ToString);
  end;
end;

// This example shows how to obtain all data nodes (objects and variables) under a given node of the OPC-UA address space. 
// For each node, it displays its browse name and node ID.
//
// 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.

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

// Perform the operation
try
{
    $NodeElements = $Client->BrowseDataNodes(
        //"http://opcua.demo-this.com:51211/UA/SampleServer", 
        "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", 
        "nsu=http://test.org/UA/Data/ ;i=10791");
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    Exit();
}

// Display results
foreach ($NodeElements as $NodeElement)
{
    printf(" s\n", $NodeElement->BrowseName, $NodeElement->NodeId);
}

// This example shows how to obtain all data nodes (objects and variables) under a given node of the OPC-UA address space.
// For each node, it displays its browse name and node ID.

mle_outputtext.Text = ""

// Instantiate the client object
OLEObject client
client = CREATE OLEObject
client.ConnectToNewObject("OpcLabs.EasyOpc.UA.EasyUAClient")

// Perform the operation
OLEObject nodeElements
TRY
    nodeElements = client.BrowseDataNodes("http://opcua.demo-this.com:51211/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10791")
CATCH (OLERuntimeError oleRuntimeError)
    mle_outputtext.Text = mle_outputtext.Text + "*** Failure: " + oleRuntimeError.Description + "~r~n"
    RETURN
END TRY

// Display results
Int i
FOR i = 0 TO nodeElements.Count - 1
    OLEObject nodeElement
    nodeElement = nodeElements.Item[i]
    mle_outputtext.Text = mle_outputtext.Text + "~r~n"
    mle_outputtext.Text = mle_outputtext.Text + "nodeElement.NodeId: " + nodeElement.NodeId.DisplayString + "~r~n"
    mle_outputtext.Text = mle_outputtext.Text + "nodeElement.DisplayName: " + nodeElement.DisplayName + "~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 data nodes (objects and variables) under a given node of the OPC-UA address space. 
# For each node, it displays its browse name and node ID.
#
# 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

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

# Perform the operation
try:
    nodeElements = client.BrowseDataNodes('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer', 'nsu=http://test.org/UA/Data/ ;i=10791')
except com_error as e:
    print('*** Failure: ' + e.args[2][1] + ': ' + e.args[2][2])
    exit()

# Display results
for nodeElement in nodeElements:
    print(nodeElement.BrowseName, ': ', nodeElement.NodeId)

REM This example shows how to obtain all data nodes (objects and variables) under a given node of the OPC-UA address space.
REM For each node, it displays its browse name and node ID.
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.

Public Sub BrowseDataNodes_Main_Command_Click()
    OutputText = ""

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    ' Perform the operation
    On Error Resume Next
    Dim NodeElements As UANodeElementCollection
    Set NodeElements = Client.BrowseDataNodes("opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10791")
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0

    ' Display results
    Dim NodeElement: For Each NodeElement In NodeElements
        OutputText = OutputText & NodeElement.BrowseName & ": " & NodeElement.NodeId & vbCrLf
    Next
End Sub

Rem This example shows how to obtain all data nodes (objects and variables) under a given node of the OPC-UA address space. 
Rem For each node, it displays its browse name and node ID.
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

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

' Perform the operation
On Error Resume Next
Dim NodeElements: Set NodeElements = Client.BrowseDataNodes("opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10791")
If Err.Number <> 0 Then
    WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
    WScript.Quit
End If
On Error Goto 0

' Display results
Dim NodeElement: For Each NodeElement In NodeElements
    WScript.Echo NodeElement.BrowseName & ": " & NodeElement.NodeId
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

Reference

_EasyUAClient Interface
_EasyUAClient Members

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