---
source_files:
  - Common/DTS.Common/Interface/TestSetups/Imports/TTS/LevelTrigger/ILevelTriggerView.cs
  - Common/DTS.Common/Interface/TestSetups/Imports/TTS/LevelTrigger/ILevelTriggerViewModel.cs
  - Common/DTS.Common/Interface/TestSetups/Imports/TTS/LevelTrigger/ILevelTrigger.cs
generated_at: "2026-04-16T03:12:36.684994+00:00"
model: "Qwen/Qwen3-Coder-Next-FP8"
schema_version: 1
sha256: "514ecd9d78491b12"
---

# LevelTrigger

## Documentation: Level Trigger Module

---

### 1. Purpose  
This module defines the core interfaces for the *Level Trigger* functionality within the TTS (presumably *Test Trigger System*) import subsystem. It establishes the contract for modeling a level-triggering mechanism—likely used to initiate or control test sequences based on signal thresholds—by decoupling data (via `ILevelTrigger`), view-model (via `ILevelTriggerViewModel`), and view (via `ILevelTriggerView`) concerns. The module serves as a foundational abstraction for UI and logic layers to interact with level-trigger configurations, including channel assignment, threshold values (in % and engineering units), and metadata like hardware serial numbers and channel counts.

---

### 2. Public Interface  

#### `ILevelTriggerView`  
- **Definition**: `public interface ILevelTriggerView : IBaseView { }`  
- **Behavior**: A marker interface extending `IBaseView`, representing the view layer for the level trigger UI component. No additional members are defined—its purpose is structural separation within the MVVM pattern.

#### `ILevelTriggerViewModel`  
- **Definition**: `public interface ILevelTriggerViewModel : IBaseViewModel`  
  - `ILevelTriggerView View { get; set; }`  
- **Behavior**: Extends `IBaseViewModel` and binds to an `ILevelTriggerView` instance. The `View` property enables two-way binding or manual assignment between the view and view-model layers.

#### `ILevelTrigger`  
- **Definition**: `public interface ILevelTrigger`  
  - **Properties**:  
    - `string Code { get; }` — Identifier for the level trigger configuration.  
    - `string JCode { get; }` — Secondary identifier (possibly job- or project-specific).  
    - `double ValuePercent { get; set; }` — Trigger threshold as a percentage (e.g., 0–100).  
    - `double ValueEU { get; set; }` — Trigger threshold in engineering units (e.g., volts, PSI).  
    - `string EULabel { get; }` — Human-readable label for the engineering unit (e.g., `"V"`, `"psi"`).  
    - `string HWSerialNumber { get; }` — Serial number of the associated hardware device.  
    - `int ChannelNumber { get; }` — Number of channels supported or currently in use.  
    - `ITTSChannelRecord Channel { get; set; }` — The *currently assigned* channel for triggering.  
    - `ITTSSetup TestSetup { get; }` — Reference to the parent test setup containing this trigger.  
    - `ITTSChannelRecord[] AvailableChannels { get; }` — List of channels eligible for assignment.  
    - `bool IsActive { get; }` — Indicates whether the level trigger is currently active/enabled.  
    - `bool IsModified { get; set; }` — Flag indicating whether the configuration has unsaved changes.  
  - **Methods**:  
    - `void Refresh()` — Updates the `AvailableChannels` collection and potentially reassigns `Channel` (e.g., if current channel becomes unavailable).  
    - `void Add(ITTSChannelRecord channel)` — Adds a channel to the `AvailableChannels` list.  
    - `void Remove(ITTSChannelRecord channel)` — Removes a channel from `AvailableChannels`; if `Channel == channel`, it is unassigned.  
    - `byte[] GetBytes()` — Returns a deterministic byte sequence for hashing (e.g., for change detection or serialization).  

---

### 3. Invariants  
- `Channel` must be `null` or an element of `AvailableChannels`.  
- `ChannelNumber` reflects the count of channels in `AvailableChannels` (though not explicitly enforced—implementation-dependent).  
- `ValuePercent` and `ValueEU` represent the *same* threshold in different units; consistency between them is expected but not enforced by the interface.  
- `IsActive` and `IsModified` are independent flags; `IsModified` does not imply `IsActive`, and vice versa.  
- `Refresh()` must ensure `AvailableChannels` is up-to-date and `Channel` remains valid (or becomes `null` if no valid channel remains).  

---

### 4. Dependencies  

#### *This module depends on*:  
- `DTS.Common.Base` (for `IBaseView`, `IBaseViewModel`)  
- `DTS.Common.Interface.TestSetups.Imports.TTS.ReadFile` (for `ITTSChannelRecord`, `ITTSSetup`)  

#### *This module is depended on by*:  
- UI layers (via `ILevelTriggerView` and `ILevelTriggerViewModel`)  
- Logic layers managing test setup configurations (via `ILevelTrigger`)  
- Serialization/hashing utilities (via `GetBytes()`)  

*Note*: Concrete implementations of `ITTSChannelRecord` and `ITTSSetup` are defined in the referenced namespace (`DTS.Common.Interface.TestSetups.Imports.TTS.ReadFile`), but their details are not included here.

---

### 5. Gotchas  
- **Ambiguity in `ChannelNumber`**: The interface does not clarify whether `ChannelNumber` represents the *total capacity* of the hardware or the *current count* of `AvailableChannels`.  
- **No validation on `ValuePercent`/`ValueEU`**: The interface allows arbitrary `double` values; implementations must enforce ranges (e.g., 0–100 for `%`).  
- **`Refresh()` semantics**: The summary states it "updates available channels and Channel", but does not specify whether `Channel` is reset to `null` if no valid channel remains, or if it attempts to preserve the current assignment.  
- **`IsModified` lifecycle**: The interface exposes `IsModified` as a settable property, but does not define when it should be set (e.g., by user input, programmatic changes, or explicit save events).  
- **No thread-safety guarantees**: All members are non-atomic; concurrent access to `Channel`, `AvailableChannels`, or `IsModified` may require external synchronization.  
- **None identified from source alone** for `ILevelTriggerView` and `ILevelTriggerViewModel` beyond structural MVVM assumptions.