Opc.Ua.Client.Session.Call C# (CSharp) Method

        public IList<object> Call(NodeId objectId, NodeId methodId, params object[] args)
        {
            VariantCollection inputArguments = new VariantCollection();
            
            if (args != null)
            {
                for (int ii = 0; ii < args.Length; ii++)
                {
                    inputArguments.Add(new Variant(args[ii]));
                }
            }
                                            
            CallMethodRequest request = new CallMethodRequest();

            request.ObjectId       = objectId;
            request.MethodId       = methodId;
            request.InputArguments = inputArguments;

            CallMethodRequestCollection requests = new CallMethodRequestCollection();
            requests.Add(request);

            CallMethodResultCollection results;
            DiagnosticInfoCollection diagnosticInfos;

            ResponseHeader responseHeader = Call(
                null,
                requests,
                out results,
                out diagnosticInfos);

            ClientBase.ValidateResponse(results, requests);
            ClientBase.ValidateDiagnosticInfos(diagnosticInfos, requests);
            
            if (StatusCode.IsBad(results[0].StatusCode))
            {
                throw ServiceResultException.Create(results[0].StatusCode, 0, diagnosticInfos, responseHeader.StringTable);
            }

            List<object> outputArguments = new List<object>();

            foreach (Variant arg in results[0].OutputArguments)
            {
                outputArguments.Add(arg.Value);
            }

            return outputArguments;
        }
        #endregion

        /// <summary>
        /// Acknowledges one or more events.
        /// </summary>
        public int[] AcknowledgeEvents(
            Session session,
            string comment,
            string acknowledgerId,
            AeAcknowledgeRequest[] requests)
        {
            if (session == null || !session.Connected)
            {
                throw ComUtils.CreateComException(ResultIds.E_FAIL);
            }

            StringBuilder buffer = new StringBuilder();
            buffer.Append('[');
            buffer.Append(acknowledgerId);
            buffer.Append(']');

            if (!String.IsNullOrEmpty(comment))
            {
                buffer.Append(comment);
            }

            // wrap the comment once.
            Variant commentToWrite = new Variant(new LocalizedText(buffer.ToString()));

            int[] errors = new int[requests.Length];
            CallMethodRequestCollection methodsToCall = new CallMethodRequestCollection();

            for (int ii = 0; ii < requests.Length; ii++)
            {
                int cookie = requests[ii].Cookie;

                AeEvent e = null;

                lock (m_lock)
                {
                    // look up the event.
                    if (!m_events.TryGetValue(cookie, out e))
                    {
                        errors[ii] = ResultIds.E_INVALIDARG;

                        if (cookie < m_counter)
                        {
                            errors[ii] = ResultIds.S_ALREADYACKED;
                        }
                        
                        continue;
                    }
                    
                    if (e.SourceName != requests[ii].SourceName)
                    {
                        errors[ii] = ResultIds.E_INVALIDARG;
                        continue;
                    }

                    if (e.ConditionName != requests[ii].ConditionName)
                    {
                        errors[ii] = ResultIds.E_INVALIDARG;
                        continue;
                    }

                    if (e.ActiveTime != requests[ii].ActiveTime)
                    {
                        errors[ii] = ResultIds.E_INVALIDTIME;
                        continue;
                    }
                    
                    // check that the cookie is still valid.
                    string conditionId = GetConditionId(e);
                    int expectedCookie = 0;

                    if (!m_cookies.TryGetValue(conditionId, out expectedCookie))
                    {
                        errors[ii] = ResultIds.S_ALREADYACKED;
                        continue;
                    }

                    // check cookie.
                    if (expectedCookie != cookie)
                    {
                        errors[ii] = ResultIds.E_INVALIDARG;
                        continue;
                    }

                    m_events.Remove(cookie);
                }

                CallMethodRequest request = new CallMethodRequest();
                request.MethodId = Opc.Ua.MethodIds.AcknowledgeableConditionType_Acknowledge;
                request.ObjectId = e.ConditionId;
                request.InputArguments.Add(new Variant(e.EventId));
                request.InputArguments.Add(commentToWrite);
                request.Handle = ii;
                methodsToCall.Add(request);
            }

            if (methodsToCall.Count > 0)
            {
                try
                {
                    // call the server.
                    CallMethodResultCollection results = null;
                    DiagnosticInfoCollection diagnosticInfos = null;

                    session.Call(
                        null,
                        methodsToCall,
                        out results,
                        out diagnosticInfos);

                    // verify that the server returned the correct number of results.
                    ClientBase.ValidateResponse(results, methodsToCall);
                    ClientBase.ValidateDiagnosticInfos(diagnosticInfos, methodsToCall);

                    // process results.
                    for (int ii = 0; ii < methodsToCall.Count; ii++)
                    {
                        int index = (int)methodsToCall[ii].Handle;

                        if (StatusCode.IsBad(results[ii].StatusCode))
                        {
                            errors[ii] = ResultIds.E_FAIL;
                            continue;
                        }
                    }
                }
                catch (Exception)
                {
                    // report error.
                    for (int ii = 0; ii < methodsToCall.Count; ii++)
                    {
                        int index = (int)methodsToCall[ii].Handle;
                        errors[ii] = ResultIds.E_FAIL;
                    }
                }
            }

            return errors;
        }