OPC Studio User's Guide and Reference
Examples - OPC Unified Architecture - Find applications and their endpoints
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.NET

// This example shows how to obtain application URLs of all OPC Unified Architecture servers, using specified discovery URI
// strings.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.Discovery;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    class FindLocalApplications
    {
        public static void Main1()
        {

            string[] discoveryUriStrings =
            {
                "opc.tcp://opcua.demo-this.com:4840/UADiscovery",
                "http://opcua.demo-this.com/UADiscovery/Default.svc",
                "http://opcua.demo-this.com:52601/UADiscovery"
            };

            // Instantiate the client object.
            var client = new EasyUAClient();

            // Obtain collection of application elements.
            UADiscoveryElementCollection discoveryElementCollection;
            try
            {
                discoveryElementCollection = client.FindLocalApplications(discoveryUriStrings, UAApplicationTypes.Server);
            }
            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["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
            //discoveryElementCollection["opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"].ApplicationUriString: urn:opcua.demo-this.com:UA Sample Server
            //discoveryElementCollection["http://opcua.demo-this.com:51211/UA/SampleServer"].ApplicationUriString: urn:opcua.demo-this.com:UA Sample Server
            //discoveryElementCollection["https://opcua.demo-this.com:51212/UA/SampleServer/"].ApplicationUriString: urn:opcua.demo-this.com:UA Sample Server
            //discoveryElementCollection["opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"].ApplicationUriString: urn:Test-PC:UA Sample Server
        }
    }
}

COM

// This example shows how to obtain application URLs of all OPC Unified Architecture servers, using specified discovery URI strings.
//
// Find all latest examples here : https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

class procedure FindLocalApplications.Main;
const
  UAApplicationTypes_Server = 1;
var
  Client: OpcLabs_EasyOpcUA_TLB._EasyUAClient;
  Count: Cardinal;
  Element: OleVariant;
  DiscoveryElement: _UADiscoveryElement;
  DiscoveryElementEnumerator: IEnumVariant;
  DiscoveryElements: _UADiscoveryElementCollection;
  DiscoveryUriStrings: OleVariant;
begin
  DiscoveryUriStrings := VarArrayCreate([0, 2], varVariant);
  DiscoveryUriStrings[0] := 'opc.tcp://opcua.demo-this.com:4840/UADiscovery';
  DiscoveryUriStrings[1] := 'http://opcua.demo-this.com/UADiscovery/Default.svc';
  DiscoveryUriStrings[2] := 'http://opcua.demo-this.com:52601/UADiscovery';

  // Instantiate the client object
  Client := CoEasyUAClient.Create;

  // Obtain collection of application elements
  try
    DiscoveryElements := Client.FindLocalApplications(DiscoveryUriStrings, UAApplicationTypes_Server);
  except
    on E: EOleException do
    begin
      WriteLn(Format('*** Failure: %s', [E.GetBaseException.Message]));
      Exit;
    end;
  end;

  // Display results
  DiscoveryElementEnumerator := DiscoveryElements.GetEnumerator;
  while (DiscoveryElementEnumerator.Next(1, Element, Count) = S_OK) do
  begin
    DiscoveryElement := IUnknown(Element) as _UADiscoveryElement;
    WriteLn(
      'DiscoveryElements["',
      DiscoveryElement.DiscoveryUriString,
      '".ApplicationUriString: ',
      DiscoveryElement.ApplicationUriString);
  end;

  VarClear(DiscoveryUriStrings);
end;

 

See Also

Conceptual

Examples - OPC Data Access