If you want to retrieve a list of OPC Alarms and Events servers registered on a local or remote computer, call the BrowseServers method, passing it the name or address of the remote machine (use empty string for local computer).
You will receive back a ServerElementCollection object. If you want to connect to this OPC server later in your code by calling other methods, use the built-in conversion of ServerElement to String, and pass the resulting string as a serverClass argument either directly to the method call, or to a constructor of ServerDescriptor object.
Each ServerElement contains information gathered about one OPC server found on the specified machine, including things like the server’s CLSID, ProgID, vendor name, and readable description.
.NET
// This example shows how to obtain all ProgIDs of all OPC Alarms and Events servers on the local machine.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// 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.
using System;
using System.Diagnostics;
using OpcLabs.EasyOpc;
using OpcLabs.EasyOpc.AlarmsAndEvents;
using OpcLabs.EasyOpc.OperationModel;
namespace DocExamples.AlarmsAndEvents._EasyAEClient
{
class BrowseServers
{
public static void Main1()
{
// Instantiate the client object.
var client = new EasyAEClient();
ServerElementCollection serverElements;
try
{
serverElements = client.BrowseServers("");
}
catch (OpcException opcException)
{
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message);
return;
}
foreach (ServerElement serverElement in serverElements)
{
Debug.Assert(serverElement != null);
Console.WriteLine("serverElements[\"{0}\"].ProgId: {1}", serverElement.Clsid, serverElement.ProgId);
}
}
}
}
' This example shows how to obtain all ProgIDs of all OPC Alarms and Events servers on the local machine.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' 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.
Imports OpcLabs.EasyOpc
Imports OpcLabs.EasyOpc.AlarmsAndEvents
Imports OpcLabs.EasyOpc.OperationModel
Namespace AlarmsAndEvents._EasyAEClient
Friend Class BrowseServers
Public Shared Sub Main1()
Dim client = New EasyAEClient()
Dim serverElements As ServerElementCollection
Try
serverElements = client.BrowseServers("")
Catch opcException As OpcException
Console.WriteLine("*** Failure: {0}", opcException.GetBaseException().Message)
Exit Sub
End Try
For Each serverElement As ServerElement In serverElements
Debug.Assert(serverElement IsNot Nothing)
Console.WriteLine("serverElements[""{0}""].ProgId: {1}", serverElement.Clsid, serverElement.ProgId)
Next serverElement
End Sub
End Class
End Namespace
COM
Rem This example shows how to obtain all ProgIDs of all OPC Alarms and Events servers on the local machine.
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 Client: Set Client = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient")
On Error Resume Next
Dim ServerElements: Set ServerElements = Client.BrowseServers("")
If Err.Number <> 0 Then
WScript.Echo "*** Failure: " & Err.Source & ": " & Err.Description
WScript.Quit
End If
On Error Goto 0
Dim ServerElement: For Each ServerElement In ServerElements
WScript.Echo "ServerElements(""" & ServerElement.UrlString & """).ProgId: " & ServerElement.ProgId
Next
Python
# This example shows how to obtain all ProgIDs of all OPC Alarms and Events servers on the local machine.
#
# 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 .
# 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.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
# Import .NET namespaces.
from OpcLabs.EasyOpc.AlarmsAndEvents import *
from OpcLabs.EasyOpc.OperationModel import *
# Instantiate the client object
client = EasyAEClient()
# Perform the operation
try:
serverElements = IEasyAEClientExtension.BrowseServers(client, '')
except OpcException as opcException:
print('*** Failure: ' + opcException.GetBaseException().Message)
exit()
# Display results
for serverElement in serverElements:
assert serverElement is not None
print('ServerElements["', serverElement.ClsidString, '"]: ', serverElement.ProgId, sep='')
See Also
