---
source_files:
  - Common/DTS.Common/Events/GroupTemplates/TemplateChannelList/TemplateChannelListOrderChangedEvent.cs
  - Common/DTS.Common/Events/GroupTemplates/TemplateChannelList/TemplateChannelListSelectionChangedEvent.cs
  - Common/DTS.Common/Events/GroupTemplates/TemplateChannelList/TemplateChannelListRequiredChangedEvent.cs
generated_at: "2026-04-17T16:36:14.988730+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "e9ebc9c1d84a9eda"
---

# Documentation: Template Channel List Events

## 1. Purpose

This module defines three Prism event types for broadcasting changes related to template channel lists within the group templates subsystem. These events enable loosely-coupled communication between components when channel order changes, selection state changes, or required channel state changes occur. All events follow the Prism Event Aggregator pattern, extending `PubSubEvent<T>`.

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## 2. Public Interface

### `TemplateChannelListOrderChangedEvent`
**Signature:** `public class TemplateChannelListOrderChangedEvent : PubSubEvent<IGroupTemplateChannel>`

An event that publishes `IGroupTemplateChannel` payloads when the order of channels in a template channel list has changed.

---

### `TemplateChannelListSelectionChangedEvent`
**Signature:** `public class TemplateChannelListSelectionChangedEvent : PubSubEvent<IGroupTemplateChannel>`

An event that publishes `IGroupTemplateChannel` payloads when the selection state within a template channel list has changed.

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### `TemplateChannelListRequiredChangedEvent`
**Signature:** `public class TemplateChannelListRequiredChangedEvent : PubSubEvent<TemplateChannelListRequiredChangeEventArgs>`

An event that publishes `TemplateChannelListRequiredChangeEventArgs` payloads when the "required" state of template channels has changed.

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### `TemplateChannelListRequiredChangeEventArgs`
**Signature:** `public class TemplateChannelListRequiredChangeEventArgs`

A payload class carrying information about required channel changes.

| Property | Type | Description |
|----------|------|-------------|
| `Consumer` | `object` | The consumer object associated with the change. |
| `Channels` | `IGroupTemplateChannel[]` | Array of channels affected by the required change. |

**Constructor:**
```csharp
public TemplateChannelListRequiredChangeEventArgs(object o, IGroupTemplateChannel[] channels)
```

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## 3. Invariants

- All three event classes inherit from `PubSubEvent<T>` from Prism, ensuring they work with the Prism Event Aggregator pattern.
- `TemplateChannelListOrderChangedEvent` and `TemplateChannelListSelectionChangedEvent` both use `IGroupTemplateChannel` as their payload type.
- `TemplateChannelListRequiredChangedEvent` uses `TemplateChannelListRequiredChangeEventArgs` as its payload type, which encapsulates both a consumer reference and an array of channels.
- `TemplateChannelListRequiredChangeEventArgs.Channels` is an array (not a collection), set at construction time with no null validation in the constructor.

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## 4. Dependencies

**This module depends on:**
- `DTS.Common.Interface.GroupTemplate` — provides the `IGroupTemplateChannel` interface used as payload type
- `Prism.Events` — provides