---
source_files:
  - Common/DTS.Common/Events/DTS.Viewer/ViewerSettings/CalibrationBehaviorSettableInViewerChangedEvent.cs
  - Common/DTS.Common/Events/DTS.Viewer/ViewerSettings/ViewerSettingsVisibilityChangedEvent.cs
generated_at: "2026-04-17T16:37:52.583907+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "4781a254be509f2c"
---

# Documentation: Viewer Settings Events

## 1. Purpose

This module defines two Prism event classes used for decoupled communication within the DTS Viewer subsystem. These events facilitate pub/sub messaging related to viewer settings state changes—specifically, calibration behavior configuration and visibility toggling of the viewer settings UI. Both events leverage Prism's `PubSubEvent<T>` base class to enable loosely-coupled component communication.

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## 2. Public Interface

### `CalibrationBehaviorSettableInViewerChangedEvent`
- **Signature:** `public class CalibrationBehaviorSettableInViewerChangedEvent : PubSubEvent<bool>`
- **Behavior:** A typed event that carries a `bool` payload indicating whether calibration behavior can be set in the viewer. Publishers broadcast the boolean state; subscribers receive it via the Prism event aggregation mechanism.

### `ViewerSettingsVisibilityChangedEvent`
- **Signature:** `public class ViewerSettingsVisibilityChangedEvent : PubSubEvent<Visibility>`
- **Behavior:** A typed event that carries a `System.Windows.Visibility` payload. Publishers broadcast visibility state changes (e.g., `Visible`, `Hidden`, `Collapsed`); subscribers receive the new visibility value.

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## 3. Invariants

- **Payload types are fixed:** `CalibrationBehaviorSettableInViewerChangedEvent` always carries `bool`; `ViewerSettingsVisibilityChangedEvent` always carries `Visibility`.
- **Inheritance contract:** Both classes inherit from `PubSubEvent<T>` and do not override or extend any members, relying entirely on the Prism base implementation.
- **Namespace consistency:** Both types reside in `DTS.Common.Events` regardless of their file location within `DTS.Viewer/ViewerSettings/` subdirectories.

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## 4. Dependencies

### This module depends on:
- `Prism.Events` — Provides `PubSubEvent<T>` base class for event aggregation
- `System.Windows` — Provides `Visibility` enum (used by `ViewerSettingsVisibilityChangedEvent` only)

### What depends on this module:
- **Unclear from source alone.** Consumers would be any component that publishes or subscribes to these events via Prism's `IEventAggregator`, but such usages are not present in the provided files.

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## 5. Gotchas

- **Namespace/file path mismatch:** The files are located in `Common/DTS.Common/Events/DTS.Viewer/ViewerSettings/`, but the declared namespace is `DTS.Common.Events`. The `// ReSharper disable CheckNamespace` directive suppresses IDE warnings about this discrepancy. This may indicate a deliberate organizational choice or historical refactoring artifact.
- **No explicit constructors or members:** Both classes are empty declarations inheriting from `PubSubEvent<T>`. This is idiomatic for Prism events but may confuse developers expecting explicit publish/subscribe methods on the class itself—those are accessed via `IEventAggregator.GetEvent<T>()`.