Discovers available OPC-UA servers and returns information about them, using the default discovery host.
Syntax
Return Value
Returns a collection of application elements (usually servers,
OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement).
This method never returns null
(Nothing
in Visual Basic).
The individual elements of the returned value are never null
(Nothing
in Visual Basic).
Exceptions
Example
// This example shows how to obtain application URLs of all OPC Unified Architecture servers on a given 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 OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.Discovery;
using OpcLabs.EasyOpc.UA.OperationModel;
namespace UADocExamples._EasyUAClient
{
class DiscoverLocalServers
{
public static void Overload1()
{
// Instantiate the client object.
var client = new EasyUAClient();
// Obtain collection of server elements.
UADiscoveryElementCollection discoveryElementCollection;
try
{
discoveryElementCollection = client.DiscoverLocalServers("opcua.demo-this.com");
}
catch (UAException uaException)
{
Console.WriteLine($"*** Failure: {uaException.GetBaseException().Message}");
return;
}
// Display results.
foreach (UADiscoveryElement discoveryElement in discoveryElementCollection)
Console.WriteLine($"discoveryElementCollection[\"{discoveryElement.DiscoveryUriString}\"].ApplicationUriString: {discoveryElement.ApplicationUriString}");
// Example output:
//
//discoveryElementCollection["opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"].ApplicationUriString: urn: DEMO - 5:UA Sample Server
//discoveryElementCollection["http://opcua.demo-this.com:51211/UA/SampleServer"].ApplicationUriString: urn: DEMO - 5:UA Sample Server
//discoveryElementCollection["https://opcua.demo-this.com:51212/UA/SampleServer/"].ApplicationUriString: urn: DEMO - 5:UA Sample Server
//discoveryElementCollection["http://opcua.demo-this.com:62543/Quickstarts/AlarmConditionServer"].ApplicationUriString: urn: opcua.demo - this.com:Quickstart Alarm Condition Server
//discoveryElementCollection["opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer"].ApplicationUriString: urn: opcua.demo - this.com:Quickstart Alarm Condition Server
}
}
}
# This example shows how to obtain application URLs of all OPC Unified Architecture servers on a given machine.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in PowerShell on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PowerShell .
# 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.
#requires -Version 5.1
using namespace OpcLabs.EasyOpc.UA
using namespace OpcLabs.EasyOpc.UA.Discovery
using namespace OpcLabs.EasyOpc.UA.OperationModel
# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUA.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUAComponents.dll"
# Instantiate the client object.
$client = New-Object EasyUAClient
# Obtain collection of server elements.
try {
$discoveryElementCollection = [IEasyUAClientExtension]::DiscoverLocalServers($client, "opcua.demo-this.com")
}
catch [UAException] {
Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
return
}
# Display results.
foreach ($discoveryElement in $discoveryElementCollection) {
Write-Host "discoveryElementCollection[`"$($discoveryElement.DiscoveryUriString)`"].ApplicationUriString: $($discoveryElement.ApplicationUriString)"
}
# Example output:
#
#discoveryElementCollection["opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"].ApplicationUriString: urn:DEMO-5:UA Sample Server
#discoveryElementCollection["http://opcua.demo-this.com:51211/UA/SampleServer"].ApplicationUriString: urn:DEMO-5:UA Sample Server
#discoveryElementCollection["https://opcua.demo-this.com:51212/UA/SampleServer/"].ApplicationUriString: urn:DEMO-5:UA Sample Server
#discoveryElementCollection["http://opcua.demo-this.com:62543/Quickstarts/AlarmConditionServer"].ApplicationUriString: urn:opcua.demo-this.com:Quickstart Alarm Condition Server
#discoveryElementCollection["opc.tcp://opcua.demo-this.com:62544/Quickstarts/AlarmConditionServer"].ApplicationUriString: urn:opcua.demo-this.com:Quickstart Alarm Condition Server
' This example shows how to obtain application URLs of all OPC Unified Architecture servers on a given 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.UA
Imports OpcLabs.EasyOpc.UA.Discovery
Imports OpcLabs.EasyOpc.UA.OperationModel
Namespace _EasyUAClient
Friend Class DiscoverLocalServers
Public Shared Sub Overload1()
' Instantiate the client object
Dim client = New EasyUAClient()
' Obtain collection of server elements
Dim discoveryElementCollection As UADiscoveryElementCollection
Try
discoveryElementCollection = client.DiscoverLocalServers("opcua.demo-this.com")
Catch uaException As UAException
Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
Exit Sub
End Try
' Display results
For Each discoveryElement As UADiscoveryElement In discoveryElementCollection
Console.WriteLine("discoveryElementCollection[""{0}""].ApplicationUriString: {1}", _
discoveryElement.DiscoveryUriString, discoveryElement.ApplicationUriString)
Next discoveryElement
' Example output:
'discoveryElementCollection["opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"].ApplicationUriString: urn:Test-PC:UA Sample Server
'discoveryElementCollection["http://opcua.demo-this.com:51211/UA/SampleServer"].ApplicationUriString: urn:Test-PC:UA Sample Server
End Sub
End Class
End Namespace
# This example shows how to obtain application URLs of all OPC Unified Architecture servers on the specified host.
#
# 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.UA import *
from OpcLabs.EasyOpc.UA.OperationModel import *
# Instantiate the client object.
client = EasyUAClient()
# Obtain collection of server elements.
try:
discoveryElementCollection = IEasyUAClientExtension.DiscoverLocalServers(client, 'opcua.demo-this.com')
except UAException as uaException:
print('*** Failure: ' + uaException.GetBaseException().Message)
exit()
# Display results.
for discoveryElement in discoveryElementCollection:
print('DiscoveryElementCollection["', discoveryElement.DiscoveryUriString, '"].ApplicationUriString: ',
discoveryElement.ApplicationUriString, sep='')
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