BrowseDataNodes Method (

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

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ElementsNotNullAttribute()>
<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)

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

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

Parameters

endpointDescriptorString: Endpoint descriptor. Identifies the OPC-UA server.
nodeDescriptorString: Node Id.

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.

Remarks

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

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.

#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.

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.

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.

// 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!
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.

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.

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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