Browses the available properties of a specified OPC item.
Browse for available item properties. Specify machine name, server class, and item ID.
Syntax
Parameters
- client
- The client object that will perform the operation.
- machineName
- Name of the machine (empty string for local computer).
- serverClass
- Contains ProgID of the OPC server to browse.
- itemId
- ID of the item for which the properties will be browsed.
Return Value
The method returns a keyed collection of
OpcLabs.EasyOpc.DataAccess.AddressSpace.DAPropertyElement values, each containing information about a particular property found. The keys of the keyed collection are the IDs of the properties.
Exceptions
Exception | Description |
System.ArgumentNullException |
A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.
This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception. |
OpcLabs.EasyOpc.OperationModel.OpcException |
The OPC "Classic" (or OPC XML-DA) operation has failed. This operation exception in uniformly used to allow
common handling of various kinds of errors. The System.Exception.InnerException always contains
information about the actual error cause.
This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately. |
Example
.NET
COM
.NET
// This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
using System;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.AddressSpace;
using OpcLabs.EasyOpc.OperationModel;
namespace DocExamples.DataAccess._EasyDAClient
{
class BrowseProperties
{
public static void Main1()
{
// Instantiate the client object.
var client = new EasyDAClient();
DAPropertyElementCollection propertyElements;
try
{
propertyElements = client.BrowseProperties("OPCLabs.KitServer.2", "Simulation.Random");
}
catch (OpcException opcException)
{
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
return;
}
foreach (DAPropertyElement propertyElement in propertyElements)
Console.WriteLine($"PropertyElements(\"{propertyElement.PropertyId.NumericalValue}\").Description: {propertyElement.Description}");
}
// Example output:
//
//PropertyElements("15008").Description: Visible
//PropertyElements("5").Description: Item Access Rights
//PropertyElements("2").Description: Item Value
//PropertyElements("7").Description: Item EU Type
//PropertyElements("15001").Description: Item Name
//PropertyElements("4").Description: Item Timestamp
//PropertyElements("1").Description: Item Canonical Data Type
//PropertyElements("103").Description: Low EU
//PropertyElements("15009").Description: Addable
//PropertyElements("6").Description: Server Scan Rate
//PropertyElements("15000").Description: Item ID
//PropertyElements("3").Description: Item Quality
}
}
# This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
#requires -Version 5.1
using namespace OpcLabs.EasyOpc.OperationModel
using namespace OpcLabs.EasyOpc.DataAccess
# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicCore.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassic.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcClassicComponents.dll"
# Instantiate the client object.
$client = New-Object EasyDAClient
try {
$propertyElements = $client.BrowseProperties("OPCLabs.KitServer.2", "Simulation.Random")
}
catch [OpcException] {
Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
return
}
Foreach ($propertyElement in $propertyElements) {
Write-Host "PropertyElements(`"$($propertyElement.PropertyId.NumericalValue)`").Description: $($propertyElement.Description)"
}
# Example output:
#
#PropertyElements("15008").Description: Visible
#PropertyElements("5").Description: Item Access Rights
#PropertyElements("2").Description: Item Value
#PropertyElements("7").Description: Item EU Type
#PropertyElements("15001").Description: Item Name
#PropertyElements("4").Description: Item Timestamp
#PropertyElements("1").Description: Item Canonical Data Type
#PropertyElements("103").Description: Low EU
#PropertyElements("15009").Description: Addable
#PropertyElements("6").Description: Server Scan Rate
#PropertyElements("15000").Description: Item ID
#PropertyElements("3").Description: Item Quality
# This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and
# description.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
# Import .NET namespaces.
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.OperationModel import *
# Instantiate the client object.
client = EasyDAClient()
# Perform the operation.
try:
propertyElements = IEasyDAClientExtension.BrowseProperties(client, '', 'OPCLabs.KitServer.2', 'Simulation.Random')
except OpcException as opcException:
print('*** Failure: ' + opcException.GetBaseException().Message)
exit()
# Display results.
for propertyElement in propertyElements:
print('PropertyElements[', propertyElement.PropertyId.NumericalValue, '].Description: ', propertyElement.Description,
sep='')
' This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.AddressSpace
Imports OpcLabs.EasyOpc.OperationModel
Namespace DataAccess._EasyDAClient
Partial Friend Class BrowseProperties
Shared Sub Main1()
Dim client = New EasyDAClient()
Dim propertyElements As DAPropertyElementCollection
Try
propertyElements = client.BrowseProperties("OPCLabs.KitServer.2", "Simulation.Random")
Catch opcException As OpcException
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
Exit Sub
End Try
For Each propertyElement In propertyElements
Console.WriteLine($"PropertyElements(""{propertyElement.PropertyId.NumericalValue}"").Description: {propertyElement.Description}")
Next propertyElement
End Sub
' Example output
'
'PropertyElements("15008").Description: Visible
'PropertyElements("5").Description: Item Access Rights
'PropertyElements("2").Description: Item Value
'PropertyElements("7").Description: Item EU Type
'PropertyElements("15001").Description: Item Name
'PropertyElements("4").Description: Item Timestamp
'PropertyElements("1").Description: Item Canonical Data Type
'PropertyElements("103").Description: Low EU
'PropertyElements("15009").Description: Addable
'PropertyElements("6").Description: Server Scan Rate
'PropertyElements("15000").Description: Item ID
'PropertyElements("3").Description: Item Quality
End Class
End Namespace
// This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
class procedure BrowseProperties.Main;
var
Client: OpcLabs_EasyOpcClassic_TLB._EasyDAClient;
Count: Cardinal;
Element: OleVariant;
ServerDescriptor: _ServerDescriptor;
NodeDescriptor: _DANodeDescriptor;
PropertyElement: _DAPropertyElement;
PropertyElementEnumerator: IEnumVariant;
PropertyElements: _DAPropertyElementCollection;
begin
ServerDescriptor := CoServerDescriptor.Create;
ServerDescriptor.ServerClass := 'OPCLabs.KitServer.2';
NodeDescriptor := CoDANodeDescriptor.Create;
NodeDescriptor.ItemId := 'Simulation.Random';
// Instantiate the client object
Client := CoEasyDAClient.Create;
try
PropertyElements := Client.BrowseProperties(
ServerDescriptor,
NodeDescriptor);
except
on E: EOleException do
begin
WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
Exit;
end;
end;
PropertyElementEnumerator := PropertyElements.GetEnumerator;
while (PropertyElementEnumerator.Next(1, Element, Count) = S_OK) do
begin
PropertyElement := IUnknown(Element) as _DAPropertyElement;
WriteLn('PropertyElements("', PropertyElement.PropertyId.NumericalValue, '").Description: ', PropertyElement.Description);
end;
end;
// This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
$ServerDescriptor = new COM("OpcLabs.EasyOpc.ServerDescriptor");
$ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$NodeDescriptor = new COM("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor");
$NodeDescriptor->ItemID = "Simulation.Random";
$Client = new COM("OpcLabs.EasyOpc.DataAccess.EasyDAClient");
try
{
$PropertyElements = $Client->BrowseProperties($ServerDescriptor, $NodeDescriptor);
}
catch (com_exception $e)
{
printf("*** Failure: %s\n", $e->getMessage());
Exit();
}
foreach ($PropertyElements as $PropertyElement)
{
printf("PropertyElements(\"s\").Descriptions\n", $PropertyElement->PropertyID->NumericalValue, $PropertyElement->Description);
}
REM This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
REM
REM Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Private Sub BrowseProperties_Main_Command_Click()
OutputText = ""
Dim serverDescriptor As New serverDescriptor
serverDescriptor.ServerClass = "OPCLabs.KitServer.2"
Dim nodeDescriptor As New DANodeDescriptor
nodeDescriptor.itemId = "Simulation.Random"
' Instantiate the client object
Dim client As New EasyDAClient
On Error Resume Next
Dim propertyElements As DAPropertyElementCollection
Set propertyElements = client.BrowseProperties(serverDescriptor, nodeDescriptor)
If Err.Number <> 0 Then
OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
Exit Sub
End If
On Error GoTo 0
Dim propertyElement: For Each propertyElement In propertyElements
OutputText = OutputText & "propertyElements(""" & propertyElement.propertyId.NumericalValue & """).Description: " & propertyElement.Description & vbCrLf
Next
End Sub
Rem This example shows how to enumerate all properties of an OPC item. For each property, it displays its Id and description.
Rem
Rem Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Option Explicit
Dim ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
Dim NodeDescriptor: Set NodeDescriptor = CreateObject("OpcLabs.EasyOpc.DataAccess.DANodeDescriptor")
NodeDescriptor.ItemID = "Simulation.Random"
Dim EasyDAClient: Set EasyDAClient = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
On Error Resume Next
Dim PropertyElements: Set PropertyElements = EasyDAClient.BrowseProperties(ServerDescriptor, NodeDescriptor)
If Err.Number <> 0 Then
WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
WScript.Quit
End If
On Error Goto 0
Dim PropertyElement: For Each PropertyElement In PropertyElements
WScript.Echo "PropertyElements(""" & PropertyElement.PropertyID.NumericalValue & """).Description: " & PropertyElement.Description
Next
// This example shows how to enumerate all properties of an OPC XML-DA item. For each property, it displays its Id and description.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
using System;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.AddressSpace;
using OpcLabs.EasyOpc.OperationModel;
namespace DocExamples.DataAccess.Xml
{
class BrowseProperties
{
public static void Main1Xml()
{
// Instantiate the client object.
var client = new EasyDAClient();
DAPropertyElementCollection propertyElements;
try
{
propertyElements = client.BrowseProperties("http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx", "Dynamic/Analog Types/Int");
}
catch (OpcException opcException)
{
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
return;
}
foreach (DAPropertyElement propertyElement in propertyElements)
Console.WriteLine($"PropertyElements(\"{propertyElement.PropertyId.NumericalValue}\").Description: {propertyElement.Description}");
}
// Example output:
//
//PropertyElements("1").Description: Item Canonical DataType
//PropertyElements("2").Description: Item Value
//PropertyElements("3").Description: Item Quality
//PropertyElements("4").Description: Item Timestamp
//PropertyElements("5").Description: Item Access Rights
//PropertyElements("6").Description: Server Scan Rate
//PropertyElements("7").Description: Item EU Type
//PropertyElements("8").Description: Item EU Info
//PropertyElements("102").Description: High EU
//PropertyElements("103").Description: Low EU
}
}
# This example shows how to enumerate all properties of an OPC XML-DA item. For each property, it displays its Id and description.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
# Import .NET namespaces.
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.DataAccess import *
# Instantiate the client object.
client = EasyDAClient()
try:
propertyElements = client.BrowseProperties(ServerDescriptor('http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx'), DANodeDescriptor('Dynamic/Analog Types/Int'))
except OpcException as opcException:
print('*** Failure: ' + opcException.GetBaseException().Message, sep='')
exit()
for propertyElement in propertyElements:
print('PropertyElements("', propertyElement.PropertyId.NumericalValue, '").Description: ', propertyElement.Description, sep='')
# Example output:
#
#PropertyElements("1").Description: Item Canonical DataType
#PropertyElements("2").Description: Item Value
#PropertyElements("3").Description: Item Quality
#PropertyElements("4").Description: Item Timestamp
#PropertyElements("5").Description: Item Access Rights
#PropertyElements("6").Description: Server Scan Rate
#PropertyElements("7").Description: Item EU Type
#PropertyElements("8").Description: Item EU Info
#PropertyElements("102").Description: High EU
#PropertyElements("103").Description: Low EU
' This example shows how to enumerate all properties of an OPC XML-DA item. For each property, it displays its Id and description.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.AddressSpace
Imports OpcLabs.EasyOpc.OperationModel
Namespace DataAccess.Xml
Partial Friend Class BrowseProperties
Shared Sub Main1Xml()
Dim client = New EasyDAClient()
Dim propertyElements As DAPropertyElementCollection
Try
propertyElements = client.BrowseProperties("http://opcxml.demo-this.com/XmlDaSampleServer/Service.asmx", "Dynamic/Analog Types/Int")
Catch opcException As OpcException
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
Exit Sub
End Try
For Each propertyElement In propertyElements
Console.WriteLine($"PropertyElements(""{propertyElement.PropertyId.NumericalValue}"").Description: {propertyElement.Description}")
Next propertyElement
End Sub
' Example output
'
'PropertyElements("1").Description: Item Canonical DataType
'PropertyElements("2").Description: Item Value
'PropertyElements("3").Description: Item Quality
'PropertyElements("4").Description: Item Timestamp
'PropertyElements("5").Description: Item Access Rights
'PropertyElements("6").Description: Server Scan Rate
'PropertyElements("7").Description: Item EU Type
'PropertyElements("8").Description: Item EU Info
'PropertyElements("102").Description: High EU
'PropertyElements("103").Description: Low EU
End Class
End Namespace
Requirements
Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows
See Also