TryParse Method (_UABrowsePathParser)

Attempts to parse a string containing an absolute browse path.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<CanBeNullAttribute()>
Function TryParse( _
   ByVal value As String, _
   ByRef browsePath As Object _
) As StringParsingError

'Usage
 
Dim instance As _UABrowsePathParser
Dim value As String
Dim browsePath As Object
Dim value As StringParsingError
 
value = instance.TryParse(value, browsePath)

[CanBeNull()]
StringParsingError TryParse( 
   string value,
   out object browsePath
)

[CanBeNull()]
StringParsingError^ TryParse( 
   String^ value,
   [Out] Object^ browsePath
)

Parameters

value: The string containing the absolute browse path to be parsed.
browsePath: OpcLabs.EasyOpc.UA.Navigation.UABrowsePath. If successful, the browse path object corresponding to the input string.

Return Value

Returns null if successful; otherwise, some OpcLabs.BaseLib.IStringParsingError indicating the reason of the failure.

Example

.NET

// Attempts to parse an absolute OPC-UA browse path and displays its starting node and elements.

using System;
using OpcLabs.BaseLib;
using OpcLabs.EasyOpc.UA.Navigation;
using OpcLabs.EasyOpc.UA.Navigation.Parsing;

namespace UADocExamples._UABrowsePathParser
{
    class TryParse
    {
        public static void Main1()
        {
            var browsePathParser = new UABrowsePathParser();

            IStringParsingError stringParsingError = browsePathParser.TryParse(
                "[ObjectsFolder]/Data/Static/UserScalar", 
                out UABrowsePath browsePath);

            // Display results
            if (!(stringParsingError is null))
            {
                Console.WriteLine("*** Error: {0}", stringParsingError);
                return;
            }

            Console.WriteLine("StartingNodeId: {0}", browsePath.StartingNodeId);

            foreach (UABrowsePathElement browsePathElement in browsePath.Elements)
                Console.WriteLine(browsePathElement);

            // Example output:
            // StartingNodeId: ObjectsFolder
            // /Data
            // /Static
            // /UserScalar
        }
    }
}

# Attempts to parse an absolute OPC-UA browse path and displays its starting node and elements.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.Navigation import *
from OpcLabs.EasyOpc.UA.Navigation.Parsing import *


browsePathParser = UABrowsePathParser()

stringParsingError, browsePath = browsePathParser.TryParse('[ObjectsFolder]/Data/Static/UserScalar', None)

# Display results.
if stringParsingError is not None:
    print('*** Error: ', stringParsingError, sep='')
    exit()

print('StartingNodeId: ', browsePath.StartingNodeId, sep='')

print()
for browsePathElement in browsePath.Elements:
    print(browsePathElement)

print()
print('Finished.')

' Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Imports System
Imports OpcLabs.BaseLib
Imports OpcLabs.EasyOpc.UA.Navigation
Imports OpcLabs.EasyOpc.UA.Navigation.Parsing

Namespace _UABrowsePathParser
    Friend Class TryParse
        Public Shared Sub Main1()
            Dim browsePathParser = New UABrowsePathParser()

            Dim browsePath As UABrowsePath = Nothing
            Dim stringParsingError As IStringParsingError = browsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", browsePath)

            ' Display results
            If Not stringParsingError Is Nothing Then
                Console.WriteLine("*** Error: {0}", stringParsingError)
                Exit Sub
            End If

            Console.WriteLine("StartingNodeId: {0}", browsePath.StartingNodeId)

            For Each browsePathElement As UABrowsePathElement In browsePath.Elements
                Console.WriteLine(browsePathElement)
            Next browsePathElement

            ' Example output:
            ' StartingNodeId: ObjectsFolder
            ' /Data
            ' /Static
            ' /UserScalar
        End Sub
    End Class
End Namespace

Object Pascal
PHP
Visual Basic (VB 6.0)

// Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

class procedure TryParse.Main;
var
  BrowsePath: _UABrowsePath;
  BrowsePathElement: _UABrowsePathElement;
  BrowsePathParser: OpcLabs_EasyOpcUA_TLB._UABrowsePathParser;
  BrowsePathResult: OleVariant;
  Count: Cardinal;
  Element: OleVariant;
  ElementEnumerator: IEnumVariant;
  StringParsingError: _StringParsingError;
begin
  BrowsePathParser := CoUABrowsePathParser.Create;

  StringParsingError := BrowsePathParser.TryParse('[ObjectsFolder]/Data/Static/UserScalar', BrowsePathResult);

  // Display results
  if StringParsingError <> nil then
  begin
    WriteLn('*** Error: ', StringParsingError.ToString);
    Exit;
  end;

  BrowsePath := IUnknown(BrowsePathResult) as _UABrowsePath;
  WriteLn('StartingNodeId: ', BrowsePath.StartingNodeId.ToString);

  WriteLn('Elements:');
  ElementEnumerator := BrowsePath.Elements.GetEnumerator;
  while (ElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    BrowsePathElement := IUnknown(Element) as _UABrowsePathElement;
    WriteLn(BrowsePathElement.ToString);
  end;

  // Example output:
  // StartingNodeId: ObjectsFolder
  // Elements:
  // /Data
  // /Static
  // /UserScalar

end;

// Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

$BrowsePath = new COM("OpcLabs.EasyOpc.UA.Navigation.UABrowsePath");

$BrowsePathParser = new COM("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser");

$StringParsingError = $BrowsePathParser->TryParse("[ObjectsFolder]/Data/Static/UserScalar", $BrowsePath);

// Display results
if (!is_null($StringParsingError)) {
    printf("*** Error: %s\n", $StringParsingError);
    exit();
}

printf("StartingNodeId: %s\n", $BrowsePath->StartingNodeId);

printf("Elements:\n");

for ($i = 0; $i < $BrowsePath->Elements->Count; $i++)
{
    printf("%s\n", $BrowsePath->Elements[$i]);
}

// Example output:
// StartingNodeId: ObjectsFolder
// Elements:
// /Data
// /Static
// /UserScalar

Rem Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Private Sub TryParse_Main_Command_Click()
    OutputText = ""
    
    Dim BrowsePathParser As New UABrowsePathParser

    Dim stringParsingError As stringParsingError
    Dim browsePath As Variant
    Set stringParsingError = BrowsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", browsePath)
    
    ' Display results
    If Not stringParsingError Is Nothing Then
        OutputText = OutputText & "*** Error: " & stringParsingError & vbCrLf
        Exit Sub
    End If
    
    OutputText = OutputText & "StartingNodeId: " & browsePath.StartingNodeId & vbCrLf
    
    OutputText = OutputText & "Elements:" & vbCrLf
    Dim BrowsePathElement: For Each BrowsePathElement In browsePath.Elements
        OutputText = OutputText & BrowsePathElement & vbCrLf
    Next

    ' Example output:
    'StartingNodeId: ObjectsFolder
    'Elements:
    '/Data
    '/Static
    '/UserScalar
End Sub

Object Pascal
PHP
Visual Basic (VB 6.0)
VBScript

// Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

class procedure TryParse.Main;
var
  BrowsePath: _UABrowsePath;
  BrowsePathElement: _UABrowsePathElement;
  BrowsePathParser: OpcLabs_EasyOpcUA_TLB._UABrowsePathParser;
  BrowsePathResult: OleVariant;
  Count: Cardinal;
  Element: OleVariant;
  ElementEnumerator: IEnumVariant;
  StringParsingError: _StringParsingError;
begin
  BrowsePathParser := CoUABrowsePathParser.Create;

  StringParsingError := BrowsePathParser.TryParse('[ObjectsFolder]/Data/Static/UserScalar', BrowsePathResult);

  // Display results
  if StringParsingError <> nil then
  begin
    WriteLn('*** Error: ', StringParsingError.ToString);
    Exit;
  end;

  BrowsePath := IUnknown(BrowsePathResult) as _UABrowsePath;
  WriteLn('StartingNodeId: ', BrowsePath.StartingNodeId.ToString);

  WriteLn('Elements:');
  ElementEnumerator := BrowsePath.Elements.GetEnumerator;
  while (ElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    BrowsePathElement := IUnknown(Element) as _UABrowsePathElement;
    WriteLn(BrowsePathElement.ToString);
  end;

  // Example output:
  // StartingNodeId: ObjectsFolder
  // Elements:
  // /Data
  // /Static
  // /UserScalar

end;

// Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

$BrowsePath = new COM("OpcLabs.EasyOpc.UA.Navigation.UABrowsePath");

$BrowsePathParser = new COM("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser");

$StringParsingError = $BrowsePathParser->TryParse("[ObjectsFolder]/Data/Static/UserScalar", $BrowsePath);

// Display results
if (!is_null($StringParsingError)) {
    printf("*** Error: %s\n", $StringParsingError);
    exit();
}

printf("StartingNodeId: %s\n", $BrowsePath->StartingNodeId);

printf("Elements:\n");

for ($i = 0; $i < $BrowsePath->Elements->Count; $i++)
{
    printf("%s\n", $BrowsePath->Elements[$i]);
}

// Example output:
// StartingNodeId: ObjectsFolder
// Elements:
// /Data
// /Static
// /UserScalar

Rem Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Private Sub TryParse_Main_Command_Click()
    OutputText = ""
    
    Dim BrowsePathParser As New UABrowsePathParser

    Dim stringParsingError As stringParsingError
    Dim browsePath As Variant
    Set stringParsingError = BrowsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", browsePath)
    
    ' Display results
    If Not stringParsingError Is Nothing Then
        OutputText = OutputText & "*** Error: " & stringParsingError & vbCrLf
        Exit Sub
    End If
    
    OutputText = OutputText & "StartingNodeId: " & browsePath.StartingNodeId & vbCrLf
    
    OutputText = OutputText & "Elements:" & vbCrLf
    Dim BrowsePathElement: For Each BrowsePathElement In browsePath.Elements
        OutputText = OutputText & BrowsePathElement & vbCrLf
    Next

    ' Example output:
    'StartingNodeId: ObjectsFolder
    'Elements:
    '/Data
    '/Static
    '/UserScalar
End Sub

Rem Attempts to parses an absolute  OPC-UA browse path and displays its starting node and elements.

Option Explicit

Dim BrowsePathParser: Set BrowsePathParser = CreateObject("OpcLabs.EasyOpc.UA.Navigation.Parsing.UABrowsePathParser")
Dim BrowsePath
Dim StringParsingError: Set StringParsingError = BrowsePathParser.TryParse("[ObjectsFolder]/Data/Static/UserScalar", BrowsePath)

' Display results
If Not (StringParsingError Is Nothing) Then
    WScript.Echo "*** Error: " & StringParsingError
    WScript.Quit
End If

WScript.Echo "StartingNodeId: " & BrowsePath.StartingNodeId

WScript.Echo "Elements:"
Dim BrowsePathElement: For Each BrowsePathElement In BrowsePath.Elements
    WScript.Echo BrowsePathElement
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

_UABrowsePathParser Interface
_UABrowsePathParser Members

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