---
source_files:
  - DTS Viewer/DTS.Viewer.Modules/DTS.Viewer.ChartOptions/Model/ChartOptionsModel.cs
generated_at: "2026-04-16T11:19:24.422198+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "a2e58408ee52b3f9"
---

# Documentation: ChartOptionsModel.cs

## 1. Purpose

`ChartOptionsModel` is a state-bearing model class that encapsulates all configuration options for chart display within the DTS Viewer application. It manages chart unit types (EU, mV, V, PSD, FFT), time units, Y-axis scaling modes, filter selections, cursor behavior, and axis locking states. The class implements `INotifyPropertyChanged` (via `BasePropertyChanged`) to support data binding and coordinates with a parent `IChartOptionsViewModel` to publish changes and execute commands.

---

## 2. Public Interface

### Class Signature
```csharp
public class ChartOptionsModel : Common.Base.BasePropertyChanged, IChartOptionsModel
```

### Properties

| Property | Type | Default | Description |
|----------|------|---------|-------------|
| `DisplayingVolts` | `bool` | `false` | Toggles between Volts (true) and millivolts (false) display. Raises `OnPropertyChanged` for `"MVOrV"` and `"UnitTypeDescription"` when changed. |
| `MVOrV` | `string` | — | Read-only. Returns `"V"` if `DisplayingVolts` is true, otherwise `"mV"`. |
| `IsDigitalChannel` | `bool` | `false` | Indicates whether the channel is digital. |
| `SupportsADC` | `bool` | `true` | Indicates ADC support. |
| `SupportsMV` | `bool` | `true` | Indicates millivolt support. |
| `UnitType` | `ChartUnitTypeEnum` | `ChartUnitTypeEnum.EU` | The unit type for the chart. Changing this sets `ReadData = true` and auto-adjusts `Filter` based on unit type. |
| `UnitTypeDescription` | `string` | — | Read-only. Returns `"V"` or `"mV"` for `ChartUnitTypeEnum.mV`, otherwise returns `UnitType.ToString()`. |
| `TimeUnitType` | `TimeUnitTypeEnum` | `TimeUnitTypeEnum.MS` | Time unit for the X-axis. Sets `ReadData = true` on change. |
| `TimeUnitTypeDescription` | `string` | `"MS"` | String representation of `TimeUnitType`. |
| `SelectedFilter` | `IFilterClass` | `FilterClass(Unfiltered)` | The selected software filter. Sets `ReadData = true` on change. |
| `MinFixedY` | `double` | `0.00` | Minimum Y-axis value for fixed range. |
| `MaxFixedY` | `double` | `0.00` | Maximum Y-axis value for fixed range. |
| `MinFixedT` | `double` | `0.00` | Minimum X-axis (time) value for fixed range. |
| `MaxFixedT` | `double` | `0.00` | Maximum X-axis (time) value for fixed range. |
| `FullScaleValues` | `List<double>` | — | Returns `_euValues` for EU/PSD unit types, otherwise `_fullScaleValues`. |
| `SelectedFullScaleValue` | `double` | `100` | Currently selected full-scale value. |
| `LockedT` | `bool` | `false` | Indicates if the X-axis is locked. |
| `LockedY` | `bool` | `false` | Indicates if the Y-axis is locked. |
| `ShowCursor` | `bool` | `false` | Cursor visibility. Calls `Parent?.ShowCusor(value)` on change. |
| `CurrentCursorValues` | `string` | `""` | String representation of current cursor values. |
| `YRange` | `YRangeScaleEnum` | `YRangeScaleEnum.AutoRange` | Y-axis range mode. Setting to `Fixed` automatically sets `LockedY = true`. |
| `Filter` | `FilterOptionEnum` | `FilterOptionEnum.TestSetupDefault` | Filter option enum. Sets `ReadData = true` on change. |
| `Parent` | `IChartOptionsViewModel` | `null` | Reference to parent view model. |
| `CanPublishChanges` | `bool` | `true` | Controls whether property changes trigger `Parent?.PublishChanges()`. |
| `IsCursorsAvailable` | `bool` | `false` | Indicates if cursors are available for the current context. |
| `T0Cursor` | `bool` | `false` | T0 cursor flag. |
| `MinMaxCursors` | `bool` | `false` | Min/Max cursors flag. |
| `ReadData` | `bool` | `false` | Flag indicating data should be re-read. |
| `IsSaved` | `bool` | — | Read-only auto-property (no setter visible). |
| `DecimateData` | `bool` | `false` | Getter returns `false` if `UnitType` is `PSD` or `FFT`, otherwise returns backing field value. |
| `WidthPoints` | `long` | `0` | Width points for decimation. |

### Commands

| Command | Type | Description |
|---------|------|-------------|
| `ResetZoomCommand` | `DelegateCommand` | Executes `ResetZoomMethod()`, which delegates to `Parent.ResetZoomMethod()`. |
| `ResetTCommand` | `DelegateCommand` | Executes `ResetTMethod()`, which delegates to `Parent.ResetTMethod()`. |
| `SaveToPDFCommand` | `DelegateCommand` | Executes `SaveToPDFMethod()`, which delegates to `Parent.SaveToPDFMethod()`. |

### Methods

| Method | Signature | Description |
|--------|-----------|-------------|
| `ChartOptionsModel` | `ctor()` | Empty parameterless constructor. |
| `SetSelectedFilterToUnfilteredNoRead` | `void SetSelectedFilterToUnfilteredNoRead()` | Sets `_selectedFilter` to `FilterClass(Unfiltered)` with `ReadData = false`. Raises `OnPropertyChanged("SelectedFilter")`. |
| `OnPropertyChanged` | `void OnPropertyChanged(string propertyName)` | Raises `PropertyChanged` event. Conditionally calls `Parent?.PublishChanges()` unless the property is in an exclusion list. |

### Events

| Event | Type | Description |
|-------|------|-------------|
| `PropertyChanged` | `PropertyChangedEventHandler` | Standard INotifyPropertyChanged event. |

---

## 3. Invariants

1. **UnitType → Filter coupling**: When `UnitType` is set to anything other than `EU` or `PSD`, `Filter` is automatically set to `FilterOptionEnum.Unfiltered`. When `UnitType` is `EU` or `PSD`, `Filter` is set to `FilterOptionEnum.TestSetupDefault`.

2. **YRange → LockedY coupling**: Setting `YRange` to `YRangeScaleEnum.Fixed` automatically sets `LockedY = true`.

3. **DecimateData conditional return**: The `DecimateData` getter always returns `false` when `UnitType` is `ChartUnitTypeEnum.PSD` or `ChartUnitTypeEnum.FFT`, regardless of the backing field `_decimateData`.

4. **FullScaleValues selection**: The property returns `_euValues` list when `UnitType` is `EU` or `PSD`; otherwise returns `_fullScaleValues`.

5. **Change publishing exclusion**: The following properties do not trigger `Parent?.PublishChanges()` when changed:
   - `CanPublishChanges`, `Parent`, `ReadData`, `UnitTypeDescription`, `ShowCursor`, `LockedT`, `LockedY`, `MVOrV`, `DisplayingVolts`, `DecimateData`, `WidthPoints`

---

## 4. Dependencies

### This Module Depends On
- `System`, `System.Collections.Generic`, `System.ComponentModel` (BCL)
- `DTS.Common` — Base namespace
- `DTS.Common.Base.BasePropertyChanged` — Base class providing `SetProperty` method
- `DTS.Common.Classes.Sensors` — `FilterClass` implementation
- `DTS.Common.Enums.Viewer` — `ChartUnitTypeEnum`, `TimeUnitTypeEnum`, `FilterOptionEnum`, `YRangeScaleEnum`
- `DTS.Common.Interface` — `IChartOptionsModel` (implied), `IChartOptionsViewModel`
- `DTS.Common.Interface.Sensors.SoftwareFilters` — `IFilterClass`
- `Prism.Commands` — `DelegateCommand`

### What Depends On This Module
- **Unknown from source alone** — The `IChartOptionsViewModel` interface references this model via the `Parent` property, but concrete consumers are not visible in this file.

---

## 5. Gotchas

1. **Typo in method call**: In the `ShowCursor` setter, the code calls `Parent?.ShowCusor(_showCursor)` — note the spelling "Cusor" instead of "Cursor". This is either a typo in the method name on `IChartOptionsViewModel` or a historical naming quirk.

2. **SetSelectedFilterToUnfilteredNoRead exists as a workaround**: The method `SetSelectedFilterToUnfilteredNoRead()` specifically bypasses the automatic `ReadData = true` behavior that occurs when setting `SelectedFilter` via the property. This suggests the automatic data refresh is sometimes undesirable and requires explicit circumvention.

3. **Inconsistent property setter patterns**: Some properties use `SetProperty(ref _field, value, "PropertyName")` (e.g., `IsDigitalChannel`, `DisplayingVolts`), while others manually implement equality checks and `OnPropertyChanged` calls (e.g., `UnitType`, `MinFixedY`). This inconsistency may reflect different authors or refactoring over time.

4. **IsSaved is unassigned**: The `IsSaved` property has no setter and no initialization. The ReSharper annotation `// ReSharper disable UnassignedGetOnlyAutoProperty` at the top of the file suppresses warnings about this. Accessing this property will return `default(bool)` (`false`).

5. **ReadData side effects are implicit**: Setting `UnitType`, `TimeUnitType`, `SelectedFilter`, or `Filter` silently sets `ReadData = true`. Callers must be aware that these property changes have side effects beyond the property value itself.

6. **Historical comment FB 13120**: The comment `// FB 13120 does not need to set SelectedFilter any more since it's not using enum` and `// FB 13120 use filter class instead of cfc filter enum` reference a past bug/feature (likely FogBugz case 13120) where filter handling was refactored from an enum to a class-based approach.