DP44/enriched-partialglm/DTS Viewer/DTS.Viewer.Reports/DTS.Viewer.PSDReportSettings/ViewModel.md

---
source_files:
  - DTS Viewer/DTS.Viewer.Reports/DTS.Viewer.PSDReportSettings/ViewModel/PSDReportSettingsViewModel.cs
generated_at: "2026-04-16T11:00:01.546105+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "9dcac2937b5c346b"
---

# Documentation: PSDReportSettingsViewModel.cs

## 1. Purpose

This module provides a ViewModel for configuring PSD (Power Spectral Density) report settings within the DTS Viewer application. It acts as a mediator between the view layer and the data model, responding to graph-related events (channel selection, axis changes, graph clearing) and publishing setting changes to other system components via an event aggregator. The class follows the MVVM pattern using Prism framework conventions.

---

## 2. Public Interface

### Class: `PSDReportSettingsViewModel`
**Namespace:** `DTS.Viewer.PSDReportSettings`  
**Inherits from:** `BaseViewModel<IPSDReportSettingsModel>`  
**Implements:** `IPSDReportSettingsViewModel`

#### Properties

| Property | Type | Access | Description |
|----------|------|--------|-------------|
| `View` | `IBaseView` | get/set | Reference to the associated view; DataContext is set to `this` in constructor. |
| `Parent` | `IBaseViewModel` | get/set | Parent ViewModel reference, passed during initialization. |
| `Model` | `IPSDReportSettingsModel` | get/set | Hides base `Model` property. Backed by private `_model` field; raises `OnPropertyChanged("Model")` on set. |
| `NotificationRequest` | `InteractionRequest<Notification>` | get | Used to raise notification dialogs. |
| `ConfirmationRequest` | `InteractionRequest<Confirmation>` | get | Hides base property. Used to raise confirmation dialogs. |

#### Constructor

```csharp
public PSDReportSettingsViewModel(
    IPSDReportSettingsView view, 
    IRegionManager regionManager, 
    IEventAggregator eventAggregator, 
    IUnityContainer unityContainer)
```
Initializes the ViewModel, sets the View's DataContext, creates interaction requests, and stores references to the event aggregator and Unity container.

#### Methods

| Method | Signature | Description |
|--------|-----------|-------------|
| `Initialize` | `override void Initialize()` | Empty override. No initialization logic. |
| `Initialize` | `override void Initialize(object parameter)` | Sets `Parent` from parameter, calls `Subscribe()`, resolves `IPSDReportSettingsModel` from container, and sets `Model.Parent = this`. |
| `PublishChanges` | `void PublishChanges()` | Publishes a `PSDReportSettingsChangedEvent` with a `PSDReportSettingsChangedEventArg` containing the current `Model` and `Parent`. |

---

## 3. Invariants

1. **Parent-Child Relationship:** The `Parent` property must be an `IBaseViewModel` type; it is cast directly from the `object parameter` in `Initialize(object parameter)` without null checking.

2. **Event Filtering:** Event handlers (`OnChartAxisChanged`, `OnGraphSelectedChannelsChanged`) filter events by checking `arg?.ParentVM != Parent`. Events not matching the parent are ignored.

3. **Model Resolution:** The `Model` is resolved from the Unity container during `Initialize(object parameter)`, not injected via constructor.

4. **Publish Control:** During X-axis changes in `OnChartAxisChanged`, `Model.CanPublishChanges` is set to `false` before modifying `DataStart`/`DataEnd`, then restored to `true` before calling `PublishChanges()`.

5. **DataContext Assignment:** The View's DataContext is assigned to `this` (the ViewModel) in the constructor, not to the Model (a commented line suggests this was previously different).

---

## 4. Dependencies

### Imports (this module depends on):
- `DTS.Common.Base` - Provides `BaseViewModel<T>`
- `DTS.Common.Events` - Provides event args: `ChartAxisChangedEventArg`, `GraphClearNotificationArg`, `GraphSelectedChannelsNotificationArg`, `PSDReportSettingsChangedEvent`, `PSDReportSettingsChangedEventArg`
- `DTS.Common.Interactivity` - Provides `InteractionRequest<T>`, `Notification`, `Confirmation`
- `DTS.Common.Interface` - Provides interfaces: `IBaseView`, `IBaseViewModel`, `IPSDReportSettingsModel`, `IPSDReportSettingsView`, `IPSDReportSettingsViewModel`
- `Prism.Events` - Provides `IEventAggregator`
- `Prism.Regions` - Provides `IRegionManager`
- `Unity` - Provides `IUnityContainer`

### Consumers (what depends on this module):
- Not determinable from this source file alone. Likely consumed by View classes and/or registered in a module initialization or DI container configuration.

---

## 5. Gotchas

1. **Member Hiding:** Both `Model` and `ConfirmationRequest` properties use the `new` keyword, hiding inherited members from `BaseViewModel<T>`. This could lead to unexpected behavior if the base class is accessed polymorphically.

2. **Commented-Out Code:** Several code blocks are commented out, including:
   - A `Standalone` property
   - Y-axis handling in `OnChartAxisChanged` (lines setting `MinFixedY`/`MaxFixedY`)
   - `PublishChanges()` call in `OnGraphSelectedChannelsChanged`
   - A subscription to `CursorsAlailableChangedEvent` in `Subscribe()`
   
   This suggests incomplete features or work-in-progress that may cause confusion.

3. **Empty `Initialize()` Override:** The parameterless `Initialize()` method is empty. If base class calls this method, no initialization occurs.

4. **Direct Cast Without Validation:** In `Initialize(object parameter)`, the parameter is cast directly to `IBaseViewModel` without null or type checking, which could throw `InvalidCastException` or result in null.

5. **Unused `OnRaiseNotification` Method:** The `OnRaiseNotification` method is private with no apparent callers within this class. It may be dead code or intended for future use.