DP44/enriched-qwen3-coder-next/Common/DTS.Common/Events/ISO.md

source_files, generated_at, model, schema_version, sha256

source_files	generated_at	model	schema_version	sha256
Common/DTS.Common/Events/ISO/ExtraPropertiesChangedEvent.cs	2026-04-16T03:25:01.894095+00:00	Qwen/Qwen3-Coder-Next-FP8	1	61eef1209c66c784

ISO

1. Purpose

This module defines event infrastructure for propagating changes to extra properties within the ISO domain layer of the DTS system. Specifically, it provides a Prism-based pub/sub event (ExtraPropertiesChangedEvent) and its associated argument container (ExtraPropertiesChangedEventArgs) to decouple producers and consumers of property updates—enabling reactive UI or business logic components to respond when a collection of IExtraProperty instances is modified, while preserving provenance via Producer and Consumer references.

---

2. Public Interface

• ExtraPropertiesChangedEvent

  • Type: class inheriting from PubSubEvent<ExtraPropertiesChangedEventArgs>
  • Behavior: A Prism PubSubEvent used to publish and subscribe to notifications about changes to extra properties. Subscribers receive an ExtraPropertiesChangedEventArgs payload.

• ExtraPropertiesChangedEventArgs

  • Type: class
  • Constructor: ExtraPropertiesChangedEventArgs(IList<IExtraProperty> extraProperties, object producer, object consumer)
  • Properties:
    • IList<IExtraProperty> ExtraProperties { get; } — The updated collection of extra properties.
    • object Producer { get; } — The object instance that initiated or caused the change.
    • object Consumer { get; } — The object instance that is the intended recipient or target of the change.
  • Behavior: Encapsulates the data for an ExtraPropertiesChangedEvent payload. All properties are read-only after construction.

---

3. Invariants

• ExtraProperties is non-null (enforced by constructor assignment; no null-check is present, so passing null will result in a NullReferenceException at runtime).
• Producer and Consumer may be null (no validation is enforced in the constructor).
• The ExtraProperties list reference is immutable in terms of property exposure (only a getter), but the contents of the list are not defensively copied—consumers must treat the list as potentially mutable if the producer retains a reference.
• The event is strictly publish-once-per-change; no batching or deduplication semantics are implied.

---

4. Dependencies

• Dependencies on this module:
  • DTS.Common.Interface.ISO.ExtraProperties — Provides the IExtraProperty interface used in ExtraPropertiesChangedEventArgs.ExtraProperties.
  • Prism.Events — Provides the PubSubEvent<T> base class.
  • System.Collections.Generic — Provides IList<T>.
• Dependencies of this module:
  • This module is consumed by components that use Prism event aggregation (e.g., view models, services) to react to extra property changes in the ISO domain.
  • No other modules in this file depend on it—this is a leaf event definition.

---

5. Gotchas

• No defensive copying: The ExtraProperties list is assigned directly from the constructor argument; if the caller mutates the list after constructing the args object, subscribers may observe unexpected changes.
• No validation on Producer/Consumer: These may be null, and subscribers must handle this case explicitly.
• No versioning or metadata: The event carries no timestamp, correlation ID, or change type (e.g., add/remove/replace), limiting traceability or differential processing.
• Assumes Prism event aggregator usage: The class is tightly coupled to Prism’s PubSubEvent<T>—not usable in isolation without Prism infrastructure.
• No documentation on semantics of Producer vs Consumer: The distinction between the two is not clarified in the source—consumers must infer intent (e.g., Producer = source of change, Consumer = target component).