Reference

OpcConditionRetainPolicy Enum

since v2.55

Namespace

Opc.UaFx

Assembly

Opc.UaFx.Advanced.dll

Package

Opc.UaFx.Advanced v2.59.0

Defines the evaluation policy for the IsRetained flag within the condition lifecycle. This policy determines under which conditions a notification remains of interest to a client and stays visible during a ConditionRefresh operation.

Syntax

public enum OpcConditionRetainPolicy

Public Enum OpcConditionRetainPolicy

Inheritance

Object → ValueType → Enum → OpcConditionRetainPolicy

Fields

Name	Value	Description
ActiveOnly	2	The IsRetained flag tracks only the active physical presence of the alarm condition or its latched state. Specification Detail: This mode deviates from standard alarm behavior by ignoring acknowledgment. IsRetained is true if ActiveState == True OR if the optional LatchedState == True. Once the alarm clears (and unlatches), it immediately disappears from active client lists.
ActiveOrUnacknowledged	3	The standard OPC UA Alarm lifecycle behavior. The IsRetained flag remains true as long as the alarm is physically active, unacknowledged, or latched. Specification Detail: Aligns with OPC UA Part 9 (Clause 4.3). IsRetained evaluates to true if (ActiveState == True || AckedState == False || LatchedState == True). For types lacking IsActive, it evaluates to (AckedState == False).
ActiveOrUnconfirmed	4	Extended high-security lifecycle behavior. The IsRetained flag remains true until the alarm is inactive, acknowledged, unlatched, AND explicitly confirmed. Specification Detail: Complies with the optional extended lifecycle in OPC UA Part 9. IsRetained evaluates to true if (ActiveState == True || AckedState == False || ConfirmedState == False || LatchedState == True).
EnabledOnly	1	The IsRetained flag is strictly synchronized with the IsEnabled of the condition. Specification Detail:Retain remains true as long as EnabledState == Enabled. Changes to AckedState, ConfirmedState, or ActiveState are entirely ignored.
Manual	0	Manual control mode. The SDK does not manage the IsRetained flag automatically. Specification Detail: The application developer is fully responsible for manually setting Retain = true/false based on custom business logic via the SDK API.

Applies to

Package	Versions
Opc.UaFx.Advanced	v2.55–v2.59