QuickOPC User's Guide and Reference
FindGdsRegistrations Method (IEasyUAApplication)
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.Application Namespace > IEasyUAApplication Interface : FindGdsRegistrations Method
The endpoint of OPC UA Global Discovery Server (GDS).
Finds all registrations for this application URI in the GDS.
Syntax
'Declaration
 
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Function FindGdsRegistrations( _
   ByVal gdsEndpointDescriptor As UAEndpointDescriptor _
) As IReadOnlyDictionary(Of UANodeId,UAApplicationElement)
'Usage
 
Dim instance As IEasyUAApplication
Dim gdsEndpointDescriptor As UAEndpointDescriptor
Dim value As IReadOnlyDictionary(Of UANodeId,UAApplicationElement)
 
value = instance.FindGdsRegistrations(gdsEndpointDescriptor)

Parameters

gdsEndpointDescriptor
The endpoint of OPC UA Global Discovery Server (GDS).

Return Value

Returns a dictionary of OpcLabs.EasyOpc.UA.Discovery.UAApplicationElement objects with application registration information, keyed by a OpcLabs.EasyOpc.UA.AddressSpace.UANodeId which is the application ID identifying the registration in the GDS.
Exceptions
ExceptionDescription
A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.
The OPC UA operation has failed.
Remarks

The identity of the application itself is carried by its application URI, as given by the OpcLabs.EasyOpc.UA.Discovery.UAApplicationElement.ApplicationUriString returned by the OpcLabs.EasyOpc.UA.Application.Extensions.IEasyUAApplicationExtension.GetApplicationElement. Methods on this interface that manipulate or inspect the GDS registration use the application URI to identify the registration records belonging to this application.

Example
// Shows how to find all application's registrations in the GDS.

using System;
using System.Collections.Generic;
using Microsoft.Extensions.DependencyInjection;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.AddressSpace;
using OpcLabs.EasyOpc.UA.Application;
using OpcLabs.EasyOpc.UA.Application.Extensions;
using OpcLabs.EasyOpc.UA.Discovery;
using OpcLabs.EasyOpc.UA.Extensions;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples.Application._IEasyUAClientApplication
{
    class FindGdsRegistrations
    {
        public static void Main1()
        {
            // Define which GDS we will work with.
            UAEndpointDescriptor gdsEndpointDescriptor =
                ((UAEndpointDescriptor)"opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer")
                .WithUserNameIdentity("appadmin", "demo");

            // Obtain the client application service.
            var client = new EasyUAClient();
            IEasyUAClientApplication clientApplication = client.GetService<IEasyUAClientApplication>();

            // Display which application we are about to work with.
            Console.WriteLine("Application URI string: {0}",
                clientApplication.GetApplicationElement().ApplicationUriString);

            // Find all application's registrations in the GDS.
            IReadOnlyDictionary<UANodeId, UAApplicationElement> applicationElementDictionary;
            try
            {
                applicationElementDictionary = clientApplication.FindGdsRegistrations(gdsEndpointDescriptor);
            }
            catch (UAException uaException)
            {
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                return;
            }

            // Display results
            foreach (KeyValuePair<UANodeId, UAApplicationElement> pair in applicationElementDictionary)
            {
                Console.WriteLine();
                Console.WriteLine("Application ID: {0}", pair.Key);

                UAApplicationElement applicationElement = pair.Value;
                Console.WriteLine("Application element: {0}", applicationElement);
                Console.WriteLine("  Application URI string: {0}", applicationElement.ApplicationUriString);
                Console.WriteLine("  Discovery URI strings: {0}", applicationElement.DiscoveryUriStrings);
                Console.WriteLine("  Product URI string: {0}", applicationElement.ProductUriString);
            }
        }
    }
}
// Shows how to find all application's registrations in the GDS.

class procedure FindGdsRegistrations.Main;
var
  ApplicationElement: _UAApplicationElement;
  ApplicationElementDictionary: _UANodeIdUAApplicationElementReadOnlyDictionary;
  ApplicationId: _UANodeId;
  Count: Cardinal;
  Element: OleVariant;
  Enumerator: IEnumVARIANT;
  Client: _EasyUAClient;
  ClientApplication: _EasyUAClientApplication;
  GdsEndpointDescriptor: _UAEndpointDescriptor;
begin
  // Define which GDS we will work with.
  GdsEndpointDescriptor := CoUAEndpointDescriptor.Create;
  GdsEndpointDescriptor.UrlString := 'opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer';
  GdsEndpointDescriptor.UserIdentity.UserNameTokenInfo.UserName := 'appadmin';
  GdsEndpointDescriptor.UserIdentity.UserNameTokenInfo.Password := 'demo';

  // Obtain the client application service.
  Client := CoEasyUAClient.Create;
  ClientApplication := IInterface(Client.GetServiceByName('OpcLabs.EasyOpc.UA.Application.IEasyUAClientApplication, OpcLabs.EasyOpcUA')) as _EasyUAClientApplication;

  // Display which application we are about to work with.
  WriteLn('Application URI string: ', ClientApplication.GetApplicationElement.ApplicationUriString);

  // Find all application's registrations in the GDS.
  try
    ApplicationElementDictionary := ClientApplication.FindGdsRegistrations(GdsEndpointDescriptor);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
    end;
  end;

  // Display results
  Enumerator := ApplicationElementDictionary.GetEnumerator;
  while (Enumerator.Next(1, Element, Count) = S_OK) do
  begin
    WriteLn;
    ApplicationId := IUnknown(Element.Key) as _UANodeId;
    WriteLn('Application ID: ', ApplicationId.ToString);

    ApplicationElement := IUnknown(Element.Value) as _UAApplicationElement;
    WriteLn('  Application URI string: ', ApplicationElement.ApplicationUriString);
    WriteLn('  Discovery URI string: ', ApplicationElement.DiscoveryUriString);
    WriteLn('  Product URI string: ', ApplicationElement.ProductUriString);
  end;
end;
' Shows how to find all application's registrations in the GDS.

Imports Microsoft.Extensions.DependencyInjection
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.AddressSpace
Imports OpcLabs.EasyOpc.UA.Application
Imports OpcLabs.EasyOpc.UA.Application.Extensions
Imports OpcLabs.EasyOpc.UA.Discovery
Imports OpcLabs.EasyOpc.UA.Extensions
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace UADocExamples.Application._IEasyUAClientApplication
    Friend Class FindGdsRegistrations
        Public Shared Sub Main1()

            ' Define which GDS we will work with.
            Dim gdsEndpointDescriptor As UAEndpointDescriptor =
                New UAEndpointDescriptor("opc.tcp://opcua.demo-this.com:58810/GlobalDiscoveryServer") _
                .WithUserNameIdentity("appadmin", "demo")

            ' Obtain the client application service.
            Dim client = New EasyUAClient()
            Dim clientApplication = client.GetService(Of IEasyUAClientApplication)()

            ' Display which application we are about to work with.
            Console.WriteLine("Application URI string: {0}",
                clientApplication.GetApplicationElement().ApplicationUriString)

            ' Find all application's registrations in the GDS.
            Dim applicationElementDictionary As IReadOnlyDictionary(Of UANodeId, UAApplicationElement)
            Try
                applicationElementDictionary = clientApplication.FindGdsRegistrations(gdsEndpointDescriptor)
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException.Message)
                Exit Sub
            End Try

            ' Display results
            For Each pair In applicationElementDictionary
                Console.WriteLine()
                Console.WriteLine("Application ID: {0}", pair.Key)

                Dim applicationElement = pair.Value
                Console.WriteLine("Application element: {0}", applicationElement)
                Console.WriteLine("  Application URI string: {0}", applicationElement.ApplicationUriString)
                Console.WriteLine("  Discovery URI strings: {0}", applicationElement.DiscoveryUriStrings)
                Console.WriteLine("  Product URI string: {0}", applicationElement.ProductUriString)
            Next pair
        End Sub
    End Class
End Namespace
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2012 R2, Windows Server 2016; .NET Core, .NET 6: Linux, macOS, Microsoft Windows

See Also