System.Collections.Generic.List.Add(tParameter)

public static ICollection<ProcessInstanceAggregate> BuildInstances(tDefinitions definitions, string processFileId)
        {
            var result = new List<ProcessInstanceAggregate>();
            var processes = definitions.Items.Where(_ => _ is tProcess).Cast<tProcess>();
            var messages = definitions.Items.Where(_ => _ is tMessage).Cast<tMessage>();
            var itemDefs = definitions.Items.Where(_ => _ is replacedemDefinition).Cast<replacedemDefinition>();
            foreach(var process in processes)
            {
                var builder = ProcessInstanceBuilder.New(processFileId);
                foreach(var message in messages)
                {
                    builder.AddMessage(message.id, message.name, message.itemRef?.Name);
                }

                foreach(var itemDef in itemDefs)
                {
                    builder.AddItemDef(itemDef.id, ItemKinds.Information, false, null);
                }

                foreach(var item in process.Items)
                {
                    tStartEvent startEvt;
                    tEndEvent endEvt;
                    tTask task;
                    tSequenceFlow sequenceFlow;
                    tExclusiveGateway exclusiveGateway;
                    tUserTask userTask;
                    tServiceTask serviceTask;
                    tBoundaryEvent boundaryEvent;
                    if ((startEvt = item as tStartEvent) != null)
                    {
                        builder.AddStartEvent(startEvt.id, startEvt.name, cb =>
                        {
                            Update(cb, startEvt);
                        });
                    }
                    else if ((endEvt = item as tEndEvent) != null)
                    {
                        builder.AddEndEvent(endEvt.id, endEvt.name);
                    }
                    else if ((userTask = item as tUserTask) != null)
                    {
                        builder.AddUserTask(userTask.id, userTask.name, (cb) =>
                        {
                            Update(cb, item.id, process.Items);
                            if (userTask.implementation == BPMNConstants.UserTaskImplementations.WSHUMANTASK)
                            {
                                var parameters = userTask.extensionElements?.Any.FirstOrDefault(_ => _.Name == "cmg:parameters");
                                List<tParameter> pars = new List<tParameter>();
                                if (parameters != null)
                                {
                                    var xmlSerializer = new XmlSerializer(typeof(tParameter), "http://www.omg.org/spec/BPMN/20100524/MODEL");
                                    foreach(XmlNode child in parameters.ChildNodes)
                                    {
                                        using (var txtReader = new StringReader(child.OuterXml))
                                        {
                                            pars.Add((tParameter)xmlSerializer.Deserialize(txtReader));
                                        }
                                    }
                                }

                                cb.SetWsHumanTask(userTask.wsHumanTaskDefName, pars.ToDictionary(_ => _.key, _ => _.value));
                            }
                        });
                    }
                    else if ((serviceTask = item as tServiceTask) != null)
                    {
                        builder.AddServiceTask(serviceTask.id, serviceTask.name, (cb) =>
                        {
                            Update(cb, item.id, process.Items);
                            if (serviceTask.implementation == BPMNConstants.ServiceTaskImplementations.CALLBACK)
                            {
                                cb.SetDelegate(serviceTask.delegateId);
                            }
                        });
                    }
                    else if((task = item as tTask) != null)
                    {
                        builder.AddEmptyTask(task.id, task.name, (cb)=>
                        {
                            Update(cb, item.id, process.Items);
                        });
                    }
                    else if((sequenceFlow = item as tSequenceFlow) != null)
                    {
                        builder.AddSequenceFlow(sequenceFlow.id, sequenceFlow.name, sequenceFlow.sourceRef, sequenceFlow.targetRef, sequenceFlow.conditionExpression?.Text.First());
                    }
                    else if((exclusiveGateway = item as tExclusiveGateway) != null)
                    {
                        builder.AddExclusiveGateway(exclusiveGateway.id, exclusiveGateway.name, MAPPING_GATEWAY_DIRECTIONS[exclusiveGateway.gatewayDirection], [email protected]);
                    }
                    else if ((boundaryEvent = item as tBoundaryEvent) != null)
                    {
                        builder.AddBoundaryEvent(boundaryEvent.id, boundaryEvent.name, cb =>
                        {
                            Update(cb, boundaryEvent);
                        });
                    }
                }

                result.Add(builder.Build());
            }

            return result;
        }