DP44/enriched-qwen3-coder-next/DTS Viewer/DTS.Viewer.Modules/DTS.Viewer.TestModification/ViewModel.md

source_files, generated_at, model, schema_version, sha256

source_files	generated_at	model	schema_version	sha256
DTS Viewer/DTS.Viewer.Modules/DTS.Viewer.TestModification/ViewModel/TestModificationViewModel.cs	2026-04-16T13:45:56.000728+00:00	zai-org/GLM-5-FP8	1	297454e79e1ccbbd

Documentation: TestModificationViewModel

1. Purpose

TestModificationViewModel is a Prism-based ViewModel that manages the test modification UI panel in the DTS Viewer application. It enables users to modify test data properties (T0 timing, sensitivity, line fit, descriptions, EU multipliers/offsets, filters, and data flags) for selected channels. The class coordinates between the UI, a sensor calibration database, and the broader application via event aggregation, while enforcing permission-based edit controls and providing undo/redo capabilities for modifications.

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2. Public Interface

Constructor

public TestModificationViewModel(
    ITestModificationView view, 
    IRegionManager regionManager, 
    IEventAggregator eventAggregator, 
    IUnityContainer unityContainer)

Initializes the ViewModel, sets up the View's DataContext, creates interaction requests, and subscribes to four events: RaiseNotification, GraphSelectedChannelsNotification, ShiftT0Event, and SetUseZeroForUnfilteredEvent.

Properties

Property	Type	Description
View	ITestModificationView	Gets/sets the associated view instance.
Parent	IBaseViewModel	Gets/sets the parent ViewModel reference.
Model	TestModificationModel	The model containing channel modification state. Setting updates the model's Parent reference.
PreviewCommand	DelegateCommand	Executes PreviewMethod() to preview line fit changes.
WriteCommand	DelegateCommand	Executes WriteMethod() to persist modifications after validation and user confirmation.
UndoCommand	DelegateCommand	Executes UndoMethod() to revert the last modification.
UndoAllCommand	DelegateCommand	Executes UndoAllMethod() to revert all modifications.
TestModificationVisability	bool	Controls visibility of the modification panel; true only when exactly one channel is selected.
IsBackedUp	bool	Indicates whether a backup exists for the current model state. Private setter.
UseISOCodeFilterMapping	bool	When true, forces ISOCode field filter to match channel's SoftwareFilter. Defaults to false.
UseZeroForUnfiltered	bool	Gets/sets whether to use zero for unfiltered values. Set via SetUseZeroForUnfilteredEvent.
IsFilterEnabled	bool	Gets/sets filter enabled state with property change notification.
HeaderInfo	string	Returns "TestSummaryRegion".
IsBusy	bool	Busy indicator with property change notification.
IsDirty	bool	Dirty state flag.
IsNavigationIncluded	bool	Navigation inclusion flag.
NotificationRequest	InteractionRequest<Notification>	Interaction request for notifications.
ConfirmationRequest	InteractionRequest<Confirmation>	Interaction request for confirmations.

Methods

public void UpdateDatabaseMethod()

Updates calibration in the database. Sets CalibrationId = -1, updates ModifyDate to DateTime.Now, creates a new SensorCalibration, inserts via DbOperations.SensorCalibrationsInsert(), then refreshes Model.Cal from latest database record. Publishes PageErrorEvent on failure.

public override void Initialize()

Empty override.

public override void Initialize(object parameter)

Sets Parent to the provided parameter cast as IBaseViewModel.

public void PublishChanges()

If not populating and Model.IsModifiedDataFlag is true, immediately saves the data flag modification and updates IsBackedUp. Always publishes TestModificationChangedEvent with the current model.

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3. Invariants

1. Single-Channel Selection: TestModificationVisability is true only when channels.Count == 1 && channels.Count(x => x.IsSelected) == 1. Multi-channel or no selection disables the modification panel.

2. T0 Validation: T0 shifts are validated via Model.ValidateT0() before write operations. T0 cannot shift beyond the dataset bounds (addresses case #14661).

3. Calibration Sorting: Calibration records are sorted in ascending order by CalibrationDate, then by ModifyDate as a tiebreaker (see CompareCalibrations).

4. Analog Sensor Calibration Display: Calibrations are only displayed for sensors where SensorType == 0 (analog sensors).

5. Permission-Based Controls: Edit permissions (EnableSensitivityControl, EnableLineFitControl, EnableDescriptionControl, EnableEUMultiplierControl, EnableEUOffsetControl, EnableFilterControl, IsT0Enabled, IsDataFlagEnabled) are gated by IViewerMainViewModel.DoesUserHaveEditPermission.

6. Population Guard: The static IsPopulating flag prevents PublishChanges() from executing data flag saves during model population.

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4. Dependencies

This Module Depends On:

• DTS.Common.Base (BaseViewModel<T>)
• DTS.Common.Events (PageErrorEvent, PageErrorArg, ShiftT0Event, ShiftT0EventArguments, TestModificationChangedEvent, ShowT0CursorEvent, GraphSelectedChannelsNotification, GraphSelectedChannelsNotificationArg, RaiseNotification, SetUseZeroForUnfilteredEvent)
• DTS.Common.Interactivity (Notification, Confirmation, NotificationContentEventArgs, InteractionRequest<T>)
• DTS.Common.Interface (IBaseViewModel, IViewerMainViewModel)
• DTS.Common.Interface.Sensors (ISensorDbRecord, ISensorCalDbRecord)
• DTS.Common.Settings (SettingsDB, Keys)
• DTS.Common.Storage (implied via DbOperations)
• DTS.Common.Utilities.Logging (APILogger)
• DTS.SensorDB (DbOperations, SensorCalibration)
• DTS.Viewer.ChartOptions.Model (channel types)
• DTS.Viewer.TestModification.Model (TestModificationModel, TestModelManipulation)
• Prism.Commands (DelegateCommand)
• Prism.Events (IEventAggregator)
• Prism.Regions (IRegionManager)
• Unity (IUnityContainer)

What Depends On This Module:

• ITestModificationView (the associated View)
• ITestModificationViewModel (interface consumers)
• Event subscribers to TestModificationChangedEvent

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5. Gotchas

1. Typo in Property Name: TestModificationVisability is misspelled (should be "Visibility"). This is a historical naming quirk.

2. Silent Exception Swallowing: GetLatestCalibration() catches all exceptions and returns null without logging. The comment explicitly states: "there's no access to APILogger here, so rather than adding a reference, just eat the error."

3. Malformed XML Comment: The <summary> tag for GetLatestCalibration is not properly closed (uses <summary> instead of </summary>).

4. Base Member Hiding: Multiple properties (Model, IsBusy, IsDirty, IsNavigationIncluded, PropertyChanged, OnPropertyChanged) use the new keyword to hide base class members, which may indicate design issues or legacy refactoring.

5. Static IsPopulating Flag: The IsPopulating property is static, meaning it is shared across all instances of TestModificationViewModel. This could cause unexpected behavior if multiple instances exist.

6. Hardcoded CalibrationId: UpdateDatabaseMethod() sets CalibrationId = -1 before insertion. The significance of -1 is not documented in source.

7. Database Setting Fallback: UseISOCodeFilterMapping defaults to false but is retrieved from settings in WriteMethod() with a default of true via SettingsDB.GetGlobalValueBool("UseISOCodeFilterMapping", true). The property default and settings default are inconsistent.

8. Null Check Inconsistency: Some null checks use null == sensor style while others use sensor == null (likely ReSharper-generated variations).