DP44/enriched-partialglm/DTS Viewer/DTS.Viewer.Reports/DTS.Viewer.PSDReportResults/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.PSDReportResults/ViewModel/PSDReportResultsViewModel.cs	2026-04-16T11:01:33.528546+00:00	zai-org/GLM-5-FP8	1	7cb2cb6c499c73c1

Documentation: PSDReportResultsViewModel

1. Purpose

PSDReportResultsViewModel is a Prism-based view model responsible for displaying PSD (Power Spectral Density) report results, specifically GRMS (Root Mean Square) summary data for channels. It serves as a subscriber to report update events and provides user-initiated export functionality to PDF and CSV formats. The view model participates in a parent-child relationship with another view model (passed during initialization) and filters incoming events to ensure it only processes data intended for its specific context.

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2. Public Interface

Properties

Name	Type	Description
View	IBaseView	Gets or sets the associated view instance. Assigned in constructor.
Parent	IBaseViewModel	Gets or sets the parent view model. Used to filter event subscriptions. Set during Initialize.
Results	ObservableCollection<IChannelGRMSSummary>	Collection of GRMS summary results displayed to the user. Cleared and repopulated on PSDReportGRMSValuesUpdatedEvent.
NotificationRequest	InteractionRequest<Notification>	Interaction request for showing notifications to the user.
ConfirmationRequest	InteractionRequest<Confirmation>	Interaction request for showing confirmation dialogs. Declared with new keyword (hides base member).
ExportToPDFCommand	DelegateCommand	Command that triggers PDF export by publishing SaveReportToPDFRequestedEvent. Lazily instantiated.
ExportToCSVCommand	DelegateCommand	Command that triggers CSV export by publishing SaveReportToCSVRequestedEvent. Lazily instantiated.

Methods

Signature	Description
PSDReportResultsViewModel(IPSDReportSettingsView view, IRegionManager regionManager, IEventAggregator eventAggregator, IUnityContainer unityContainer)	Constructor. Accepts an IPSDReportSettingsView (note: not IPSDReportResultsView), assigns it to View, sets DataContext to itself, and initializes interaction requests and service references.
override void Initialize(object parameter)	Initializes the view model. Expects parameter to be castable to IBaseViewModel (assigned to Parent). Creates empty Results collection and subscribes to events.

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3. Invariants

1. Parent-based event filtering: Both OnGRMSValuesUpdated and OnGraphSelectedChannelsChanged check if (Parent != arg.ParentVM) return; — events are ignored if the sender's parent view model does not match this instance's parent.

2. Results collection lifecycle: Results is instantiated as an empty ObservableCollection<IChannelGRMSSummary> in Initialize, not in the constructor. It is cleared before repopulation in OnGRMSValuesUpdated.

3. Directory derivation: The private Directory property is derived from the first selected channel's BinaryFilePath with "Binary" replaced by "Reports" via ReplaceLast. If no channels are selected, Directory is set to string.Empty.

4. Lazy command instantiation: Both ExportToPDFCommand and ExportToCSVCommand use lazy initialization via null-coalescing pattern.

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4. Dependencies

This module depends on:

• DTS.Common.Base — BaseViewModel<T>
• DTS.Common.Events — PSDReportGRMSValuesUpdatedEvent, PSDReportGRMSValuesUpdatedEventArg, GraphSelectedChannelsNotification, GraphSelectedChannelsNotificationArg, SaveReportToPDFRequestedEvent, SaveReportToPDFRequestedEventArgs, SaveReportToCSVRequestedEvent, SaveReportToCSVRequestedEventArgs
• DTS.Common.Interactivity — InteractionRequest<T>, Notification, Confirmation
• DTS.Common.Interface — IBaseView, IBaseViewModel, IPSDReportResultsViewModel, IChannelGRMSSummary, ITestChannel, IPSDReportSettingsView
• DTS.Common.Utils — ReplaceLast extension method (inferred from usage on string)
• Prism.Delegates — DelegateCommand
• Prism.Events — IEventAggregator, ThreadOption
• Prism.Regions — IRegionManager
• Unity — IUnityContainer
• System.Collections.ObjectModel — ObservableCollection<T>

What depends on this module:

• Not determinable from this source file alone. Consumers would implement IPSDReportResultsView and resolve IPSDReportResultsViewModel via the container.

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5. Gotchas

1. Constructor parameter type mismatch: The constructor accepts IPSDReportSettingsView but the class implements IPSDReportResultsViewModel. This appears inconsistent — the view type name suggests "settings" while the view model is for "results". This may be intentional coupling or a copy-paste error.

2. Member hiding with new keyword:

   • _regionManager is declared with new, hiding the base class's _regionManager.
   • ConfirmationRequest is declared with new, hiding a base class member.
   • This suggests the base class BaseViewModel<T> already defines these members, and the derived class is overriding them shadow-style rather than using proper override/virtual patterns.

3. Unused service references: _eventAggregator, _unityContainer, and _regionManager are stored as private fields despite the base class constructor already receiving them. The new keyword on _regionManager indicates potential confusion about inheritance.

4. Null-conditional handling inconsistency: OnGraphSelectedChannelsChanged uses null-conditional operators (arg?.ParentVM, arg?.SelectedChannels) while OnGRMSValuesUpdated does not. This suggests different assumptions about event argument nullability.

5. Unused imports: System.Threading.Tasks is imported but no async/await or Task usage is present in the file.