---
source_files:
  - Common/DTS.Common/Events/Groups/GroupsList/GroupListEditGroupEvent.cs
  - Common/DTS.Common/Events/Groups/GroupsList/GroupListGroupSelectedEvent.cs
generated_at: "2026-04-16T03:26:07.948442+00:00"
model: "Qwen/Qwen3-Coder-Next-FP8"
schema_version: 1
sha256: "bca3088a7f9f7005"
---

# GroupsList

## Documentation: Group List Events Module

### 1. Purpose  
This module defines two Prism-based pub/sub events used to communicate group selection and editing actions within the group list UI layer. Specifically, `GroupListEditGroupEvent` signals that a single group should be edited (via its numeric ID), while `GroupListGroupSelectedEvent` signals that a set of groups has been selected (via an array of IDs). These events decouple UI components (e.g., a group list view) from handlers (e.g., a view model or controller responsible for launching an edit dialog or performing bulk operations), enabling flexible event-driven interactions in the application’s MVVM architecture.

---

### 2. Public Interface  

#### `GroupListEditGroupEvent`
- **Signature**: `public class GroupListEditGroupEvent : PubSubEvent<int> { }`  
- **Behavior**: A Prism `PubSubEvent<int>` used to publish when a single group is selected for editing. The payload is the group’s integer ID. Subscribers receive this ID to initiate editing logic (e.g., opening an edit dialog for the group with that ID).

#### `GroupListGroupSelectedEvent`
- **Signature**: `public class GroupListGroupSelectedEvent : PubSubEvent<int[]> { }`  
- **Behavior**: A Prism `PubSubEvent<int[]>` used to publish when multiple groups are selected (e.g., via multi-select UI). The payload is an array of group IDs (`int[]`) representing the currently selected groups. Subscribers may use this to enable bulk operations (e.g., delete, assign) or update selection state.

> **Note**: Both event classes have no public methods, properties, or constructors beyond the inherited `PubSubEvent<TPayload>` behavior (e.g., `Subscribe`, `Publish`). Their sole purpose is to define strongly-typed event payloads.

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### 3. Invariants  
- `GroupListEditGroupEvent` **always** carries a single non-null `int` payload representing a valid group identifier.  
- `GroupListGroupSelectedEvent` **always** carries a non-null `int[]` payload. The array may be empty (indicating deselection of all groups) but must not be `null`.  
- IDs in both events are expected to correspond to existing groups in the system’s data model (though validation is not enforced by the event classes themselves).  
- No ordering guarantee is provided for `int[]` payloads in `GroupListGroupSelectedEvent`; the order of IDs is implementation-dependent (e.g., reflects UI selection order or internal storage order).

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### 4. Dependencies  
- **Depends on**:  
  - `Prism.Events.PubSubEvent<T>` (from the Prism library) — base class for both events.  
  - `DTS.Common` namespace — shared common library (implied by `DTS.Common.Events` namespace).  
- **Depended on by**:  
  - UI components (e.g., group list views) that publish these events on user interaction.  
  - View models or services that subscribe to these events to handle group editing or selection logic.  
  - *Inferred*: Any module handling group lifecycle operations (e.g., editing, bulk actions) will likely reference these events.

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### 5. Gotchas  
- **Misleading XML documentation**: Both events’ `<summary>` and `<remarks>` incorrectly reference `"GroupTemplateListGroupTemplateSelectedEvent"` and `"called when a template is selected"`. This appears to be copy-paste error or outdated documentation; the actual purpose relates to *groups*, not templates.  
- **Ambiguous selection semantics**: `GroupListGroupSelectedEvent`’s payload (`int[]`) does not distinguish between user-initiated selection changes (e.g., adding/removing items) and explicit "apply" actions. Subscribers must infer intent from context or additional state.  
- **No validation in event**: Neither event validates that IDs exist or are non-negative. Invalid IDs may propagate to subscribers, requiring defensive handling.  
- **Thread-safety**: As Prism `PubSubEvent` instances, events are published on the UI thread by default (unless configured otherwise), but subscribers must ensure thread-safe operations if they perform non-UI work.  
- **None identified from source alone** for behavioral quirks beyond the above.