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

source_files, generated_at, model, schema_version, sha256

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

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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

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.

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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).

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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.

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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.