BrowseDataVariables Method (

Browses the Data Variables, specifying an endpoint descriptor, and a starting Node Id.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Function BrowseDataVariables( _
   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.BrowseDataVariables(endpointDescriptorString, nodeDescriptorString)

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

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

Parameters

endpointDescriptorString: Endpoint descriptor. Identifies the OPC-UA server.
nodeDescriptorString: Node descriptor. Identifies the node in OPC server's address space.

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.

Example

// This example shows how to obtain data variables under the "Server" node
// in the address space.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

class procedure BrowseDataVariables.Main;
var
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  Count: Cardinal;
  Element: OleVariant;
  EndpointDescriptor: string;
  NodeElement: _UANodeElement;
  NodeElementEnumerator: IEnumVariant;
  NodeElements: _UANodeElementCollection;
  ServerNodeId: _UANodeId;
begin
  EndpointDescriptor := 
    //'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';

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

  // Obtain variables under "Server" node
  ServerNodeId := CoUANodeId.Create;
  ServerNodeId.StandardName := 'Server';
  try
    NodeElements := Client.BrowseDataVariables(EndpointDescriptor, ServerNodeId.ExpandedText);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  // Display results
  NodeElementEnumerator := NodeElements.GetEnumerator;
  while (NodeElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    NodeElement := IUnknown(Element) as _UANodeElement;
    WriteLn;
    WriteLn('nodeElement.NodeId: ', NodeElement.NodeId.ToString);
    WriteLn('nodeElement.NodeId.ExpandedText: ', NodeElement.NodeId.ExpandedText);
    WriteLn('nodeElement.DisplayName: ', NodeElement.DisplayName);
  end;

  // Example output:
  //
  //nodeElement.NodeId: Server_ServerStatus
  //nodeElement.NodeId.ExpandedText: nsu=http://opcfoundation.org/UA/ ;i=2256
  //nodeElement.DisplayName: ServerStatus
end;

// This example shows how to obtain data variables under the "Server" node
// in the address space.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

$EndpointDescriptor = new COM("OpcLabs.EasyOpc.UA.UAEndpointDescriptor");
$EndpointDescriptor->UrlString = 
    //"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";

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

// Obtain variables under "Server" node
$ServerNodeId = new COM("OpcLabs.EasyOpc.UA.AddressSpace.UANodeId");
$ServerNodeId->StandardName = "Server";

try
{
    $NodeElements = $Client->BrowseDataVariables($EndpointDescriptor, $ServerNodeId->ExpandedText);
}
catch (com_exception $e)
{
    printf("*** Failure: %s\n", $e->getMessage());
    exit();
}

// Display results
foreach ($NodeElements as $NodeElement)
{
    printf("\n");
    printf("nodeElement.NodeId: %s\n", $NodeElement->NodeId);
    printf("nodeElement.NodeId.ExpandedText: %s\n", $NodeElement->NodeId->ExpandedText);
    printf("nodeElement.DisplayName: %s\n", $NodeElement->DisplayName);
}

// Example output:
//
//nodeElement.NodeId: Server_ServerStatus
//nodeElement.NodeId.ExpandedText: nsu=http://opcfoundation.org/UA/ ;i=2256
//nodeElement.DisplayName: ServerStatus

REM This example shows how to obtain data variables under the "Server" node
REM in the address space.
REM
REM Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Public Sub BrowseDataVariables_Main_Command_Click()
    OutputText = ""

    Dim endpointDescriptor As String
    'endpointDescriptor = "http://opcua.demo-this.com:51211/UA/SampleServer"
    'endpointDescriptor = "https://opcua.demo-this.com:51212/UA/SampleServer/"
    endpointDescriptor = "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    ' Obtain variables under "Server" node
    Dim serverNodeId As New UANodeId
    serverNodeId.StandardName = "Server"
    
    On Error Resume Next
    Dim NodeElements As UANodeElementCollection
    Set NodeElements = Client.BrowseDataVariables(endpointDescriptor, serverNodeId.expandedText)
    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 & vbCrLf
        OutputText = OutputText & "nodeElement.NodeId: " & NodeElement.NodeId & vbCrLf
        OutputText = OutputText & "nodeElement.NodeId.ExpandedText: " & NodeElement.NodeId.expandedText & vbCrLf
        OutputText = OutputText & "nodeElement.DisplayName: " & NodeElement.DisplayName & vbCrLf
    Next
    
    ' Example output:
    '
    'nodeElement.NodeId: Server_ServerStatus
    'nodeElement.NodeId.ExpandedText: nsu=http://opcfoundation.org/UA/ ;i=2256
    'nodeElement.DisplayName: ServerStatus
End Sub

Rem This example shows how to obtain data variables under the "Server" node in the address space.
Rem
Rem Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Option Explicit

Dim endpointDescriptor: endpointDescriptor = _
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
    '"http://opcua.demo-this.com:51211/UA/SampleServer"  
    '"https://opcua.demo-this.com:51212/UA/SampleServer/"

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

' Obtain variables under "Server" node
Dim ServerNodeId: Set ServerNodeId = CreateObject("OpcLabs.EasyOpc.UA.AddressSpace.UANodeId")
ServerNodeId.StandardName = "Server"
On Error Resume Next
Dim NodeElementCollection: Set NodeElementCollection = Client.BrowseDataVariables(endpointDescriptor, ServerNodeId.ExpandedText)
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 NodeElementCollection
    WScript.Echo 
    WScript.Echo "nodeElement.NodeId: " & NodeElement.NodeId
    WScript.Echo "nodeElement.NodeId.ExpandedText: " & NodeElement.NodeId.ExpandedText
    WScript.Echo "nodeElement.DisplayName: " & NodeElement.DisplayName
Next

' Example output:
'
'nodeElement.NodeId: Server_ServerStatus
'nodeElement.NodeId.ExpandedText: nsu=http://opcfoundation.org/UA/ ;i=2256
'nodeElement.DisplayName: ServerStatus

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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