DP44/enriched-qwen3-coder-next/DataPRO/Modules/Groups/GroupImport/ViewModel.md

---
source_files:
  - DataPRO/Modules/Groups/GroupImport/ViewModel/GroupImportViewModel.cs
generated_at: "2026-04-16T04:45:51.906727+00:00"
model: "Qwen/Qwen3-Coder-Next-FP8"
schema_version: 1
sha256: "f514e88931e0b70e"
---

# GroupImportViewModel Documentation

## 1. Purpose

`GroupImportViewModel` is the central view model for the group and channel import functionality in the DTS application. It orchestrates the end-to-end workflow of importing data from `.grp` files—parsing file contents, validating sensor and field data, allowing user review and selection of groups/channels for import, and committing validated data to the database via background processing. It serves as the data context for three distinct views (`IGroupImportOptionsView`, `IGroupImportPreviewView`, `IGroupImportImportView`) and integrates with Prism’s region management, event aggregation, and Unity DI container to coordinate UI state and external service calls.

## 2. Public Interface

### Constructor
```csharp
public GroupImportViewModel(
    IGroupImportOptionsView optionsView,
    IGroupImportPreviewView previewView,
    IGroupImportImportView importView,
    IRegionManager regionManager,
    IEventAggregator eventAggregator,
    IUnityContainer unityContainer)
```
Initializes the view model, assigns views and their `DataContext`, sets up interaction requests (`NotificationRequest`, `ConfirmationRequest`), and subscribes to `RaiseNotification` and `BusyIndicatorChangeNotification` events.

### Methods
- **`void ParseSourceFiles(string userTags)`**  
  Reads and parses all `.grp` files listed in `SourceFiles`. For each file:
  - Extracts group name from file name (strips extension).
  - Assigns `userTags` to `GroupTags` and `ImportingUserTags`.
  - Parses each non-empty line using `Parse()` (supports escaped commas via parentheses).
  - Validates fields: expects 5 fields per line (`SensorSerialNumber`, `DisplayName`, `ISOCode`, `Invert`, `FullScale`).
  - Reports errors for missing sensors (unless empty), invalid invert/full-scale values, wrong field count, or empty files.
  - Populates `Groups` and calls `ProcessChannels()`.

- **`void Import()`**  
  Starts the import process on a background thread via `ThreadPool.QueueUserWorkItem(ImportFunc)`.

- **`private void ImportFunc(object o)`**  
  Background method that:
  - Fetches default channel settings via `DbOperations.GetChannelSettingDefaults()`.
  - Updates UI progress state (`ImportProgressValue`, `ImportProgressBarVisibility`, `ImportProgressColor`, `DisableUI`).
  - Iterates over included groups and their channels:
    - Skips channels with critical errors (`FileEmpty`, `InvalidSensorInput`, `SensorNotFound`).
    - For non-critical errors, uses `null` for invalid `FullScale` or `Invert`.
    - Calls `CreateGroup`, `AddChannel`, and finally `CommitGroups`.
  - Restores UI state on completion (though commented-out lines suggest UI reset is incomplete).

- **`void SetStatus(string message, Color color)`**  
  Updates `ImportProgressText`, `ImportProgressColor`, `ImportProgressBarVisibility` (collapsed), and invokes `EnableUI`.

- **`void Reset()`**  
  Clears all imported data: `SourceFiles`, `Channels`, `Groups`, progress state, and resets `ImportProgressValue` to 0.

- **`void CheckGroupName()`**  
  Validates group names:
  - Flags groups with duplicate names in the import set.
  - Flags groups whose name already exists in the application *and* `Overwrite` is `false`.
  - Sets `GroupNameHasError = true` on invalid groups.

- **`private static string[] Parse(string line)`**  
  Parses a single `.grp` line, respecting parenthetical escaping (e.g., `"this(,)is"` → one field `"this(,)is"`).

- **`private void ProcessChannels()`**  
  Flattens all channels from `Groups` into the `Channels` array.

- **`void InvalidateChannels()`**  
  Raises `PropertyChanged` for `IncompleteChannels` and `CompleteChannels` computed properties.

- **`void Cleanup()` / `Task CleanupAsync()` / `void Initialize()` / `Task InitializeAsync()` / `void Activated()`**  
  No-op stubs; likely required by Prism interfaces (`INavigationAware`, `IInitializeAsync`, etc.) but not implemented.

### Properties
- **`IGroupImportOptionsView ImportOptionsView`**, **`IGroupImportPreviewView ImportPreviewView`**, **`IGroupImportImportView ImportView`**  
  References to the three associated views.

- **`string[] SourceFiles`**  
  Array of `.grp` file paths to parse.

- **`GroupGRPImportGroup[] Groups`**  
  Parsed groups with their channels and errors.

- **`GroupGRPImportChannel[] Channels`**  
  Flattened list of all channels from `Groups`.

- **`GroupGRPImportChannel[] IncompleteChannels`**  
  Channels in included groups that have *non-recoverable* errors (e.g., `SensorNotFound`, `InvalidSensorInput`). These will *not* be imported.

- **`GroupGRPImportChannel[] CompleteChannels`**  
  Channels in included groups that either have no errors *or* have recoverable errors (`InvalidFullScaleInput`, `InvalidInvertInput`). These *will* be imported (with `null` for invalid fields).

- **`string ImportProgressText`**, **`Color ImportProgressColor`**, **`Visibility ImportProgressBarVisibility`**, **`double ImportProgressValue`**  
  UI state for the import progress bar.

- **`bool IsBusy`**  
  Bound to busy indicator; set via `OnBusyIndicatorNotification`.

- **`InteractionRequest<Notification> NotificationRequest`**, **`InteractionRequest<Confirmation> ConfirmationRequest`**  
  Prism interaction requests for showing notifications and confirmation dialogs.

- **`bool IsDirty`**  
  Read-only; always `false` (never set to `true` in source).

- **`bool IsMenuIncluded`**, **`bool IsNavigationIncluded`**  
  UI state flags (bound to menu/navigation visibility); no logic sets them beyond property change notifications.

- **`string HeaderInfo`**  
  Returns `"MainRegion"`.

### Commands
- **`DelegateCommand ImportBrowseCommand`**  
  Opens a file dialog (`OpenFileDialog`) with `Multiselect=true`, `Filter` from `StringResources.ImportFileFilter`, sets `SourceFiles`, `BrowseOk=true`, and navigates to `Steps.Preview` via `SwitchNavSteps`.

### Delegates (Settable Properties)
- **`CheckGroupExistsDelegate CheckGroupExists`**  
  Function to check if a group exists in the application.

- **`CheckSensorExistsDelegate CheckSensorExists`**  
  Function to check if a sensor exists.

- **`CreateGroupDelegate CreateGroup`**  
  Action to create a group.

- **`AddChannelToGroupDelegate AddChannel`**  
  Action to add a channel to a group.

- **`CommitGroupsDelegate CommitGroups`**  
  Action to commit groups to the database.

- **`Disable_UIDelegate DisableUI`**, **`Enable_UIDelegate EnableUI`**  
  Actions to disable/enable the UI during import.

- **`SwitchNavStepsDelegate SwitchNavSteps`**  
  Action to navigate between import steps (e.g., `Steps.Preview`).

- **`FileUtils.LogDelegate Logger`**  
  Optional logging delegate; invoked on exceptions.

## 3. Invariants

- **File Parsing**: Each `.grp` line must contain 5 comma-separated fields (or be empty/whitespace). Lines with fewer or more fields are marked with `InvalidSensorInput`.
- **Sensor Validation**: A channel is flagged `SensorNotFound` if `CheckSensorExists` is non-null, the sensor serial number is non-empty, and `CheckSensorExists(sensorSerialNumber)` returns `false`. Empty sensor serial numbers are *allowed* (per comment referencing FB13753).
- **Invert Field**: Accepts `"yes"/"no"` (case-insensitive) or `bool.TryParse`-compatible strings. Invalid values trigger `InvalidInvertInput`.
- **FullScale Field**: Must parse as `double`; otherwise, `InvalidFullScaleInput`.
- **Group Name Uniqueness**: Within the import set, duplicate group names are flagged. Across the import set and application, group names must be unique *unless* `Overwrite=true`.
- **Import Progress State**: During `ImportFunc`, `ImportProgressBarVisibility` is set to `Visible`, `DisableUI` is called, and progress is tracked. Completion logic is partially commented out, so UI may not fully reset.
- **Channel Inclusion Logic**: Only channels from groups where `Included=true` are considered for import. Channels with critical errors (`FileEmpty`, `InvalidSensorInput`, `SensorNotFound`) are skipped entirely; others may be imported with `null` for invalid fields.

## 4. Dependencies

### Imports/References
- **DTS.Common**:
  - `Events` (`IEventAggregator`, `RaiseNotification`, `BusyIndicatorChangeNotification`)
  - `Utils` (`FileUtils.LogDelegate`)
  - `Classes.Groups` (`GroupGRPImportGroup`, `GroupGRPImportChannel`, `GroupGRPImportError`)
  - `Enums.Groups` (`GroupImportEnums.Steps`, `GroupGRPImportError.Errors`)
  - `Interface.Groups` (`IGroupImportOptionsView`, `IGroupImportPreviewView`, `IGroupImportImportView`, `IGroupImportViewModel`)
  - `Storage` (`DbOperations`)
  - `Interactivity` (`InteractionRequest<T>`)
- **Prism**:
  - `Regions` (`IRegionManager`)
  - `Events` (`IEventAggregator`)
  - `DelegateCommand`
- **Unity** (`IUnityContainer`)
- **System.Windows** (`Visibility`, `Color`)
- **System.Windows.Forms** (`OpenFileDialog`)
- **StringResources** (resource strings for UI messages)

### Dependencies on External Services
- `DbOperations.GetChannelSettingDefaults()` — for default channel settings.
- `CheckSensorExists`, `CheckGroupExists`, `CreateGroup`, `AddChannel`, `CommitGroups` — injected delegates for database operations.
- `SwitchNavSteps` — navigation delegate (likely from a parent view model or shell).

## 5. Gotchas

- **Incomplete UI Reset After Import**: `ImportFunc` sets `ImportProgressBarVisibility = Visibility.Visible` and `DisableUI`, but the corresponding reset (`Visibility.Collapsed`, `EnableUI`) is commented out. This may leave the UI in a disabled state if import completes without error.
- **Empty Sensor Serial Numbers Are Allowed**: Despite `CheckSensorExists` validation, empty serial numbers bypass the `SensorNotFound` check (FB13753).
- **Partial Error Tolerance**: Channels with `InvalidFullScaleInput` or `InvalidInvertInput` are included in `CompleteChannels` and imported, but with `null` for the invalid field. This may cause downstream issues if the database or business logic does not handle `null` gracefully.
- **No Validation of Group Name Format**: Only existence and duplication are checked; no format validation (e.g., reserved characters, length limits) is implemented.
- **`Parse()` Escaping Logic**: Parentheses are treated as literal characters *only* when nested (via `leftParenCount`). A single `(` or `)` without matching pairs is still treated as a delimiter if not balanced.
- **`IsDirty` Never Set**: The `IsDirty` property is declared but never updated, so it always returns `false`.
- **`Initialize*` and `Cleanup*` Methods Are No-ops**: These likely exist to satisfy Prism interfaces but contain no logic.
- **`Channels` Property Triggers `InvalidateChannels()`**: Setting `Channels` raises property change notifications for `IncompleteChannels` and `CompleteChannels`, but these are computed properties—modifying `Channels` directly may not reflect changes in the UI if `Groups` is not updated.
- **Thread Safety**: `ImportFunc` runs on a background thread but updates UI properties directly (e.g., `ImportProgressValue`). While Prism’s `INotifyPropertyChanged` may handle thread marshaling in some cases, this pattern is fragile and may cause cross-thread exceptions if the UI framework is strict.