DP44/enriched-qwen3-coder-next/Common/DTS.Common/Interface/DTS.Viewer.md

---
source_files:
  - Common/DTS.Common/Interface/DTS.Viewer/ITabView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IDiagView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ITestsView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IStatsView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ICursorView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IViewerView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ITabItemView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IPropertyView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IViewerShellView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IGraphPropertyView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IDockPanelVerticalView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IDockPanelHorizontalView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/GroupChannelReadCalcDelegate.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IExportModule.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IViewerModule.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IPSDReportModule .cs
  - Common/DTS.Common/Interface/DTS.Viewer/ITabViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IDiagViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IStatsViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ICursorViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ITestsViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IViewerViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IPropertyViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IGraphPropertyViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IDockPanelVerticalViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IDockPanelHorizontalViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ITabItemViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IViewerShellViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IMainLiteView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IMainViewerView.cs
  - Common/DTS.Common/Interface/DTS.Viewer/ISelectedDataViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IMainViewModel.cs
  - Common/DTS.Common/Interface/DTS.Viewer/IMainLiteViewModel.cs
generated_at: "2026-04-16T03:00:55.719180+00:00"
model: "Qwen/Qwen3-Coder-Next-FP8"
schema_version: 1
sha256: "833fa0763e07cd73"
---

# Viewer Interface Module Documentation

## 1. Purpose  
This module defines the core view and view model interfaces for the DTS Viewer application’s UI layer. It establishes a contract-based architecture—following the MVVM pattern—where each interface represents a distinct UI component (e.g., tabs, panels, views, modules) and enforces a consistent relationship between view models and their corresponding views via strongly-typed `View` properties. The interfaces are intentionally minimal and declarative, serving as abstraction boundaries to decouple UI presentation logic from implementation details, enabling modular development and testability. The module is part of the `DTS.Common.Interface` namespace and relies on `DTS.Common.Base` for base contracts (`IBaseView`, `IBaseViewModel`) and `Prism.Modularity` for module lifecycle management.

## 2. Public Interface  

### View Interfaces (all inherit `IBaseView`)  
- **`ITabView`** – Marker interface for tab container views.  
- **`IDiagView`** – Marker interface for diagnostic views.  
- **`ITestsView`** – Marker interface for tests views.  
- **`IStatsView`** – Marker interface for statistics views.  
- **`ICursorView`** – Marker interface for cursor control views.  
- **`IViewerView`** – Marker interface for main viewer content views.  
- **`ITabItemView`** – Marker interface for individual tab item views.  
- **`IPropertyView`** – Marker interface for property display/edit views.  
- **`IGraphPropertyView`** – Marker interface for graph-specific property views.  
- **`IDockPanelVerticalView`** – Marker interface for vertically docked panel views.  
- **`IDockPanelHorizontalView`** – Marker interface for horizontally docked panel views.  
- **`IViewerShellView`** – Marker interface for the main shell/container view.  
- **`IMainLiteView`** – Extends `IBaseView`; defines named UI regions (`MainShell`, `MainRegion`, `NavigationRegion`, `HorizontalTabRegion`, `VerticalTabRegion`) as `StackPanel`/`ContentControl` elements.  
- **`IMainViewerView`** – Extends `IBaseView`; currently has no additional members (commented-out region properties suggest future or legacy use).  

### View Model Interfaces (all inherit `IBaseViewModel`)  
- **`ITabViewModel`** – Provides `ITabView View { get; }`.  
- **`IDiagViewModel`** – Provides `IDiagView View { get; }`.  
- **`ITestsViewModel`** – Provides `ITestsView View { get; }`.  
- **`IStatsViewModel`** – Provides `IStatsView View { get; }`.  
- **`ICursorViewModel`** – Provides `ICursorView View { get; }`.  
- **`IViewerViewModel`** – Provides `IViewerView View { get; }`.  
- **`IPropertyViewModel`** – Provides `IPropertyView View { get; }`.  
- **`IGraphPropertyViewModel`** – Provides `IGraphPropertyView View { get; }`.  
- **`IDockPanelVerticalViewModel`** – Provides `IDockPanelVerticalView View { get; }`.  
- **`IDockPanelHorizontalViewModel`** – Provides `IDockPanelHorizontalView View { get; }`.  
- **`ITabItemViewModel`** – Provides `ITabItemView View { get; }` and `ITabViewModel Parent { get; }`.  
- **`IViewerShellViewModel`** – Provides `IViewerShellView View { get; }`, `List<FrameworkElement> GetRegions()`, and `object ContextMainRegion { get; set; }`.  
- **`IMainViewerViewModel`** – Provides `IBaseView View { get; }`, `object Context*Region { get; set; }` for four named regions, and `List<FrameworkElement> GetRegions()`.  
- **`IMainLiteViewModel`** – Provides `IMainView View { get; }` (note: `IMainView` is *not defined in this file*), `object Context*Region { get; set; }` for four named regions, and `List<FrameworkElement> GetRegions()`.  
- **`ISelectedDataViewModel`** – Manages selected data context:  
  - `string SelectedDataFolder { get; set; }`  
  - `string SelectedDataFile { get; set; }`  
  - `void SelectAndIncludeDataFile(string file)` — Sets `SelectedDataFile` *and* includes it as a selected test (comment references bug #16158).  

### Delegate  
- **`SetReadCalcProgressValueDelegate`** – Signature: `void(string message = "", double value = -1D)` — Used to report progress for read/calculation operations.  

### Module Interfaces (all implement `Prism.Modularity.IModule`)  
- **`IExportModule`** – `void StartSession(); bool SessionStarted { get; }`  
- **`IViewerModule`** – `void StartSession(); bool SessionStarted { get; }`  
- **`IPSDReportModule`** – `void StartSession(); bool SessionStarted { get; }`  
*(All modules share identical lifecycle contracts: start session, track session state.)*  

## 3. Invariants  
- **View-ViewModel Pairing**: Every view model interface (`*ViewModel`) declares a read-only `View` property whose type is the corresponding view interface (`*View`).  
- **Hierarchical View Models**: `ITabItemViewModel` must have a `Parent` of type `ITabViewModel`.  
- **Region Context Management**: `IMainViewerViewModel`, `IMainLiteViewModel`, and `IViewerShellViewModel` expose `Context*Region` properties for four named regions (`MainRegion`, `NavigationRegion`, `HorizontalTabRegion`, `VerticalTabRegion`), implying these regions are expected to be set/updated at runtime.  
- **Module Lifecycle**: All module interfaces (`IExportModule`, `IViewerModule`, `IPSDReportModule`) require explicit `StartSession()` invocation and expose a `SessionStarted` state flag.  
- **Base Contracts**: All interfaces inherit from `IBaseView` (for views) or `IBaseViewModel` (for view models), enforcing a common base contract (not detailed here).  

## 4. Dependencies  
- **Internal Dependencies**:  
  - `DTS.Common.Base` (provides `IBaseView`, `IBaseViewModel`)  
  - `Prism.Modularity` (for `IModule` interface, used in module interfaces)  
- **External Dependencies**:  
  - `System.Windows` (used in `IMainLiteViewModel`, `IMainViewerViewModel`, `IViewerShellViewModel` for `FrameworkElement`, `StackPanel`, `ContentControl`)  
- **Depended Upon**:  
  - This module is a *contract layer*—other modules (e.g., UI implementations, module plugins) depend on these interfaces to implement views, view models, and Prism modules.  
  - `ISelectedDataViewModel` is likely consumed by data browsing/selection components.  
  - `SetReadCalcProgressValueDelegate` is likely used by background computation modules.  

## 5. Gotchas  
- **Missing `IMainView`**: `IMainLiteViewModel` references `IMainView View { get; }`, but `IMainView` is *not defined in this file* (or any provided file). This is a critical dependency gap.  
- **Redundant Module Interfaces**: `IExportModule`, `IViewerModule`, and `IPSDReportModule` have identical signatures—consider if a single shared interface would suffice or if future divergence is intended.  
- **`IMainViewerView` is Empty**: Its region properties are commented out, suggesting incomplete or deprecated functionality.  
- **`IViewerViewModel` Documentation Error**: Its `View` property summary says *“Gets the Tests View”* but the type is `IViewerView`, not `ITestsView`. Likely a copy-paste error in XML comments.  
- **`ISelectedDataViewModel.SelectAndIncludeDataFile` Behavior**: The method sets `SelectedDataFile` *and* includes it as a selected test—this dual responsibility is non-obvious from the name alone.  
- **No Validation Rules**: None of the interfaces enforce validation (e.g., `SelectedDataFile` must be non-null/non-empty), leaving this to implementations.  
- **Delegate Default Values**: `SetReadCalcProgressValueDelegate` uses `message = ""` and `value = -1D` as defaults; callers should interpret `-1D` as “no progress update” or “indeterminate.”  
- **No Inheritance Between View Interfaces**: Despite naming (e.g., `ITabView`, `ITabItemView`), there is no inheritance hierarchy among view interfaces—each is independent.