TryParse Method (_UABrowsePathParser)

Attempts to parse a string containing an absolute browse path.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<JetBrains.Annotations.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)

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

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

Parameters

value: The string containing the absolute browse path to be parsed.
The value of this parameter can be null (Nothing in Visual Basic).
browsePath: OpcLabs.EasyOpc.UA.Navigation.UABrowsePath. If successful, the browse path object corresponding to the input string.
The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

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

This method can return null (Nothing in Visual Basic).

Remarks

This method is pure, i.e. it does not have observable side effects.

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

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

$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.
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.

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.
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

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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