DP44/docs/ai/DTS Viewer/DTS.Viewer.Modules/DTS.Viewer.AddCalculatedChannel/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.AddCalculatedChannel/ViewModel/AddCalculatedChannelViewModel.cs	2026-04-17T16:00:17.185622+00:00	zai-org/GLM-5-FP8	1	71a9c8acbea4fb64

Documentation: AddCalculatedChannelViewModel

1. Purpose

This module provides the ViewModel for the "Add Calculated Channel" feature in the DTS Viewer application. It manages the UI logic and business rules for creating derived data channels from existing test data, supporting multiple calculation types including mathematical operations (Integral, Derivative, Sin, Cos), aggregations (SUM, Average, Resultant), and specialized biomechanical calculations (HIC, 3D IR-Tracc variants). The ViewModel handles channel selection, validation, file I/O operations, and coordinates with the event aggregation system to notify other application components of changes.

2. Public Interface

Class: AddCalculatedChannelViewModel

Inherits: BaseViewModel<IAddCalculatedChannelViewModel>
Implements: IAddCalculatedChannelViewModel

Constructor

public AddCalculatedChannelViewModel(
    IAddCalculatedChannelView view, 
    IRegionManager regionManager, 
    IEventAggregator eventAggregator,
    IUnityContainer unityContainer)

Initializes the ViewModel, sets up the View's DataContext, creates interaction requests, and registers the AddCalculatedChannelCommand.

Public Properties

Property	Type	Description
View	IBaseView	The associated view instance.
Parent	IBaseViewModel	The parent ViewModel passed during initialization.
ContextSearchRegion	object	Context for search region (usage unclear from source).
NotificationRequest	InteractionRequest<Notification>	Raises notification dialogs.
ConfirmationRequest	InteractionRequest<Confirmation>	Raises confirmation dialogs.
HeaderInfo	string	Returns "AddCalculatedChannelRegion".
IsBusy	bool	Throws NotImplementedException on get/set.
IsDirty	bool	Throws NotImplementedException on get.
IsAddCalculatedChannelIncluded	bool	Gets/sets inclusion flag.
IncludeGroupNameInISOExport	bool	Controls whether group names are included in ISO export.
DefaultDTSEncoding	int	Encoding code page for DTS file operations.
ChannelName	string	Name for the new calculated channel.
ChannelDescription	string	Auto-generated description based on selected calculation and channels.
IsoCode	string	ISO code for the channel (defaults to "NONE").
SingleChannelSelectorVisibility	bool	Controls visibility for single-channel selection UI.
HICChannelSelectorVisibility	bool	Controls visibility for HIC channel selection UI.
MultipleChannelSelectorVisibility	bool	Controls visibility for multi-channel selection UI.
ThreeDIRTRACCVisibility	bool	Controls visibility for 3D IR-Tracc channel selection UI.
CalculationList	CalculationHelper[]	Lazy-initialized list of available calculations.
SelectedCalculation	CalculationHelper	Currently selected calculation type.
ChannelList	ObservableCollection<ITestChannel>	All available input channels.
ChannelListObjects	ObservableCollection<ChannelHelper>	Wrapped channel objects with IsIncluded tracking.
AvailableHICChannels	ChannelHelper[]	Channels with acceleration units valid for HIC calculation.
HICAccelerationX	ChannelHelper	Selected X-axis acceleration channel for HIC.
HICAccelerationY	ChannelHelper	Selected Y-axis acceleration channel for HIC.
HICAccelerationZ	ChannelHelper	Selected Z-axis acceleration channel for HIC.
HICLength	int	HIC calculation length parameter (default: 16).
SourceChannel	ITestChannel	Selected source channel for single-channel calculations.
IRTraccChannelList	ObservableCollection<ChannelHelper>	Valid IR-Tracc channels.
IRTraccChannel	ChannelHelper	Selected IR-Tracc channel.
Pot1ChannelList	ObservableCollection<ChannelHelper>	Valid potentiometer 1 channels.
Pot1Channel	ChannelHelper	Selected potentiometer 1 channel.
Pot2ChannelList	ObservableCollection<ChannelHelper>	Valid potentiometer 2 channels.
Pot2Channel	ChannelHelper	Selected potentiometer 2 channel.

Public Commands

Command	Handler	Description
AddCalculatedChannelCommand	AddCalculatedChannel(object obj)	Validates input, creates calculated channel(s), writes to DTS file, and publishes refresh event.

Public Methods

public void PublishChanges()  // Throws NotImplementedException
public override void Initialize()
public override void Initialize(object parameter)
public override void Activated()
public override void Cleanup()
public bool Validate(ref List<string> errors, ref List<string> warnings, bool displayWindow)

Public Enum: Calculation

Value	Name	Description Attribute
0	Integral	"Integral"
1	DoubleIntegral	"Double Integral"
2	Derivative	"Derivative"
3	Sin	"Sin"
4	Cos	"Cos"
5	ThreeDIRTracc	"3D IR-Tracc"
6	SUM	"SUM"
7	AVE	"Average"
8	ThreeDIRTraccAbdomen	"3D IR-TRACC Abdomen"
9	ThreeDIRTraccLowerThorax	"3D IR-TRACC Lower Thorax"
10	Resultant	"Resultant"
11	HIC	"HIC"

Public Nested Classes

ChannelHelper

Wraps ITestChannel with display formatting and inclusion tracking.

Member	Type	Description
MyChannel	ITestChannel	The wrapped channel.
DisplayName	string	Formatted display name based on IsoViewMode.
ChannelName	string	Returns ToString() of the channel.
IsIncluded	bool	Tracks whether channel is included in multi-select calculations.

CalculationHelper

Wraps Calculation enum with localized string representation.

Member	Type	Description
MyCalculation	Calculation	The wrapped calculation type.
ToString()	string	Returns localized name from resources or enum name.

3. Invariants

1. Channel List Ordering: ChannelList is always sorted by AbsoluteDisplayOrder via CompareDisplayOrders comparison.

2. IR-Tracc Channel Eligibility: Channels in IRTraccChannelList must satisfy all of:

   • ChannelType equals Test.Module.AnalogInputChannel type string
   • LinearizationFormula is valid (via LinearizationFormula.IsValid())
   • ZeroMethod equals ZeroMethodType.None
   • ZeroPoint is not zero
   • FactoryExcitationVoltage is not zero

3. Potentiometer Channel Eligibility: Channels in Pot1ChannelList and Pot2ChannelList must satisfy:

   • ChannelType equals Test.Module.AnalogInputChannel type string
   • Eu (engineering units) is "deg" or "deg-ang" (case-insensitive)
   • ZeroMethod equals ZeroMethodType.None
   • FactoryExcitationVoltage is not zero

4. HIC Channel Eligibility: Channels in AvailableHICChannels must have engineering units contained in Constants.ACCELERATION_UNITS.

5. Resultant Validation: All included channels for Resultant calculation must have matching SensitivityUnits and SampleRateHz.

6. HIC Validation: HIC calculation requires all three acceleration channels (X, Y, Z) to be non-null.

7. File Backup: DTS file backup is only created if a backup file does not already exist.

4. Dependencies

Direct Dependencies (Imports)

• DTS.Common / DTS.Common.Base / DTS.Common.Utils / DTS.Common.Utilities.Logging
• DTS.Common.Classes.Viewer.Commands (for RelayCommand)
• DTS.Common.DAS.Concepts
• DTS.Common.Enums.Sensors (for ZeroMethodType)
• DTS.Common.Events (for event types)
• DTS.Common.Interactivity (for InteractionRequest, Notification, Confirmation)
• DTS.Common.Interface
• DTS.Slice.Control
• DTS.Viewer.AddCalculatedChannel.Model
• DTS.Serialization.Test (aliased as Test)
• Prism.Events (for IEventAggregator)
• Prism.Regions (for IRegionManager)
• Unity (for IUnityContainer)

Events Subscribed

• RaiseNotification → OnRaiseNotification
• TestSummaryChangeNotification → OnTestSummaryChanged

Events Published

• SetSaveButton (via SaveButtonUsability payload)
• PageErrorEvent (via PageErrorArg payload)
• RefreshTestRequestEvent (with DTS file path)
• RaiseNotification (via NotificationContentEventArgs)

Consumers

Unknown from source alone. The module is instantiated via Unity dependency injection and navigated to via Prism regions.

5. Gotchas

1. Unimplemented Members: IsBusy, IsDirty, and PublishChanges() throw NotImplementedException. These appear to be interface requirements that were never implemented.

2. HIC Save Button Logic Appears Inverted: In UpdateSaveButtonVisibility(), the HIC case sets IsUsable = true when acceleration channels are null and IsUsable = false when they are set. This appears to be a bug—the logic should likely be inverted.

   case Calculation.HIC:
       if (null == HICAccelerationX || null == HICAccelerationY || null == HICAccelerationZ)
       {
           _eventAggregator.GetEvent<SetSaveButton>().Publish(new SaveButtonUsability() { IsUsable = true }); // Suspect
       }
       else
       {
           _eventAggregator.GetEvent<SetSaveButton>().Publish(new SaveButtonUsability() { IsUsable = false }); // Suspect
       }
       break;
   

3. Member Hiding with new Keyword: The class uses new to hide inherited members (PropertyChanged, OnPropertyChanged, IsBusy, IsDirty, ConfirmationRequest). This can lead to unexpected behavior when the ViewModel is accessed via base class references.

4. Thread.Sleep in File Write: A Thread.Sleep(10) follows the file write operation in AddCalculatedChannel(). This suggests a timing-related workaround for file system operations.

5. Backup File Deletion: After successful save, the backup file is deleted only if it was created during that save operation (!backupExisted). Original backups are preserved.

6. Channel Loading Side Effect: OnTestSummaryChanged triggers lazy loading of channel data via Utils.SetChannelInfo() when ts.Channels.FirstOrDefault() == null, modifying the test metadata in place.

7. Default Encoding Fallback: If Encoding.GetEncoding(DefaultDTSEncoding) fails, the code falls back to Encoding.Default without re-throwing, potentially causing encoding mismatches.