233 lines
11 KiB
Markdown
233 lines
11 KiB
Markdown
---
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source_files:
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- DataPRO/Modules/Channels/ChannelCodes/ViewModel/ChannelCodesListViewModel.cs
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generated_at: "2026-04-16T04:56:00.828392+00:00"
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model: "Qwen/Qwen3-Coder-Next-FP8"
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schema_version: 1
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sha256: "a1a75e2ca7b7b574"
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---
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# ViewModel
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### **1. Purpose**
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The `ChannelCodesListViewModel` class serves as the view model for managing and displaying channel codes (both ISO and User-defined) in a data entry UI. It orchestrates data loading, filtering, sorting, editing (including paste, copy, delete, and validation), and persistence operations for channel codes. It acts as the intermediary between the UI (`IChannelCodesListView`) and the underlying data layer (`ChannelCode`, `ChannelCodeType`), leveraging Prism’s event aggregation for decoupled communication and Unity for dependency injection. Its primary role is to expose collections of channel codes (`ISOChannelCodes`, `UserChannelCodes`) and provide methods to manipulate and validate them before saving to the database.
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---
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### **2. Public Interface**
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#### **Properties**
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- `IChannelCodesListView View { get; set; }`
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Reference to the associated view; view model sets `View.DataContext = this`.
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- `InteractionRequest<Notification> NotificationRequest { get; }`
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Prism interaction request used to show notification popups (e.g., errors, info).
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- `InteractionRequest<Confirmation> ConfirmationRequest { get; }`
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Prism interaction request used to prompt for user confirmation (e.g., delete).
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- `event PropertyChangedEventHandler PropertyChanged`
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Standard `INotifyPropertyChanged` implementation; `OnPropertyChanged` raises it.
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- `List<IChannelCode> AllISOChannelCodes { get; set; }`
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Full list of ISO channel codes (including blank trailing row), used for sorting/filtering.
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- `List<IChannelCode> AllUserChannelCodes { get; set; }`
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Full list of User channel codes (including blank trailing row), used for sorting/filtering.
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- `ObservableCollection<IChannelCode> ISOChannelCodes { get; set; }`
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Filtered/sorted view of `AllISOChannelCodes`, bound to the UI.
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- `ObservableCollection<IChannelCode> UserChannelCodes { get; set; }`
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Filtered/sorted view of `AllUserChannelCodes`, bound to the UI.
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- `ViewModes ViewMode { get; set; }`
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Current view mode (`ISO` or `User`). Changing it updates `ISOVisibility`/`UserVisibility`.
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- `Visibility ISOVisibility { get; }`
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`Visible` if `ViewMode == ViewModes.ISO`, else `Collapsed`.
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- `Visibility UserVisibility { get; }`
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`Visible` if `ViewMode == ViewModes.User`, else `Collapsed`.
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- `bool IsBusy { get; set; }`
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Bound to busy indicator; updated via `OnBusyIndicatorNotification`.
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- `bool IsDirty { get; private set; }` *(Note: never set in source — likely unused or bug)*
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- `bool IsReadOnly { get; set; }`
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Controls editability of the view (e.g., based on permissions).
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- `bool IsMenuIncluded { get; set; }`, `bool IsNavigationIncluded { get; set; }`
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UI layout toggles.
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- `object Page { get; private set; }`
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Identifier for the page this VM serves (used in events to route to correct consumer).
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- `Func<IList<IChannelCode>> ChannelCodesFunc { get; }`
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Returns `GetAllChannels()` → `ChannelCode.ChannelCodes`.
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- `bool ShowISOStringBuilder { get; set; }`, `bool ShowChannelCodeLookupHelper { get; set; }`, `bool UniqueISOCodesRequired { get; set; }`
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UI configuration flags.
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#### **Methods**
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- `void SetPage(object page)`
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Sets the `Page` identifier used in events.
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- `void OnSetActive()`
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Loads existing channel codes from DB (`ChannelCode.GetExistingChannelCodes`), populates `AllISOChannelCodes`/`AllUserChannelCodes`, adds blank trailing rows, sorts, filters, and updates `ISOChannelCodes`/`UserChannelCodes`. Logs exceptions.
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- `void Unset()`
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Clears all channel code collections and raises property change notifications.
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- `void Initialize()`, `void Initialize(object)`, `Task InitializeAsync()`, `void Activated()`, `void Cleanup()`, `Task CleanupAsync()`
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No-op stubs (likely required by Prism interface contracts).
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- `bool Save()`
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Persists changes in three steps:
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1. Deletes removed codes (those with valid IDs not in `All*ChannelCodes`).
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2. Updates existing codes (those with valid IDs).
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3. Inserts new codes (those without valid IDs and not blank).
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Returns `true` on success; publishes `PageModifiedEvent(Status.Saved)` or `PageErrorEvent` on failure.
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- `void Remove(IChannelCode channel)`
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Removes a channel from both `All*` and `*ChannelCodes` lists, adds a blank row if the last row was removed, and publishes `PageModifiedEvent(Status.Modified)`.
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- `void MarkModified(IChannelCode channel)`
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Ensures a blank row is added after the modified channel (if it’s the last visible row), and publishes `PageModifiedEvent(Status.Modified)`.
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- `void Validate(bool bDisplayWindow)`
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Validates all ISO/User codes: checks for missing code/name, duplicate code+name pairs. Populates `errors`/`warnings` lists. If `bDisplayWindow`, publishes `PageErrorEvent`. Returns `true` if no errors.
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- `void ValidateISO(ref List<string> errors, ref List<string> warnings)`
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Validates ISO codes only (calls `CheckChannelCode`).
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- `void ValidateUser(ref List<string> errors, ref List<string> warnings)`
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Validates User codes only (calls `CheckChannelCode`).
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- `void CopySelected()`
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Copies selected items (from current `ViewMode`) into `All*ChannelCodes` (before the trailing blank row), then sorts/filters.
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- `void DeleteSelected()`
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Deletes selected items (from current `ViewMode`), adds blank row if last item deleted, clears selection, and publishes `PageModifiedEvent(Status.Modified)`.
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- `void SetISOSelection(IChannelCode[] channelCodes)`, `void SetUserSelection(IChannelCode[] channelCodes)`
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Stores selected items; triggers `PageSelectionChanged` event if `ViewMode` matches.
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- `IChannelCode[] SelectedCodes { get; }`
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Returns selected items for current `ViewMode`.
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- `void Filter(object columnTag, string searchTerm)`
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Updates `_searchTermForField` and re-applies filter (`FilterIso`/`FilterUser`).
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- `void Sort(object columnTag, bool bColumnClick)`
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Updates sort field/direction and re-applies sort (`SortIso`/`SortUser`) + filter.
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- `void OnRaiseNotification(NotificationContentEventArgs)`
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Handles `RaiseNotification` events by raising `NotificationRequest`.
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- `void OnBusyIndicatorNotification(bool)`
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Updates `IsBusy` property.
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- `void ReportErrors(string[] errors)`
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Publishes `PageErrorEvent`.
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---
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### **3. Invariants**
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- **Trailing Blank Row**:
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`AllISOChannelCodes` and `AllUserChannelCodes` always contain a trailing blank `ChannelCode` (added in `OnSetActive`, `Remove`, `MarkModified`, `Paste*`, `CopySelected`, `DeleteSelected`). This enables adding new entries.
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- **Filtering Logic**:
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`ISOChannelCodes`/`UserChannelCodes` only include rows where:
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- Both `Code` and `Name` are blank, **or**
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- `Code`/`Name` matches current search term (case-insensitive substring match).
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- **Sorting Logic**:
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Sorting uses `ChannelComparer`, which:
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- Treats blank rows (empty `Code` and `Name`) as *lowest priority* (sorted to bottom).
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- Uses `NaturalStringComparer` for case-insensitive, culture-aware comparison.
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- Sorts `Code`/`Name` fields separately for ISO/User modes.
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- **Validation Rules**:
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A channel code is invalid if:
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- `Code` is missing (for non-blank rows) → error.
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- `Name` is missing (for non-blank rows) → error.
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- Duplicate `Code` + `Name` pair exists → error.
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- **Save Order**:
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`Save()` processes deletions → updates → inserts to avoid ID/name conflicts.
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- **Event Subscription Guard**:
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`_bAddListeners` ensures only the *second* instantiation of `ChannelCodesListViewModel` subscribes to `TextPastedEvent`/`ChannelCodeCommittedEvent` (a workaround for app startup ordering).
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---
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### **4. Dependencies**
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#### **Imports/Usings (External Dependencies)**
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- `Prism.Events` (`IEventAggregator`, `EventBase`)
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- `Prism.Regions` (`IRegionManager`)
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- `Unity` (`IUnityContainer`)
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- `DTS.Common.*`:
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- `Enums.Channels.ChannelEnumsAndConstants`
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- `Events.*` (`TextPastedEvent`, `ChannelCodeCommittedEvent`, `PageModifiedEvent`, `PageErrorEvent`, `PageSelectionChanged`)
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- `Interface.Channels.ChannelCodes.*` (`IChannelCodesListView`, `IChannelCodesListViewModel`, `IChannelCode`)
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- `Utilities.*` (`NaturalStringComparer`, `Logging.APILogger`)
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- `Interactivity` (`InteractionRequest<Notification/Confirmation>`)
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#### **Internal Dependencies**
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- `ChannelCodes.Model` (`ChannelCode`, `ChannelCodeType`)
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- `DTS.Common.Enums` (`UIItemStatus`, `PageModifiedArg.Status`)
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- `Resources.StringResources` (for localized error messages)
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#### **Consumers (Inferred)**
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- `ChannelCodesListViewModel` is instantiated via Unity (constructor injection).
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- `IChannelCodesListView` binds to its properties/methods.
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- Other modules subscribe to its events (`PageModifiedEvent`, `PageErrorEvent`, `PageSelectionChanged`).
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- `ChannelCodeCommittedEvent` publisher (e.g., a dialog) calls `OnChannelCodesCommitted`.
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---
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### **5. Gotchas**
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- **`_bAddListeners` Hack**:
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A static boolean `_bAddListeners` prevents *first* instantiation from subscribing to events (due to app startup ordering). Only the *second* instance subscribes. This is fragile and non-obvious.
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- **`IsDirty` Never Set**:
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The `IsDirty` property is declared but never updated (no assignment in source). Likely dead code or incomplete implementation.
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- **`SelectedCodes` Null Safety**:
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`GetSelectedISOCodes`/`GetSelectedUserCodes` return `null` if `_selectedISOItems`/`_selectedUserItems` are `null`. Consumers must handle `null`.
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- **Paste Behavior Depends on `tag`**:
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`PasteIso`/`PasteUser` use `tag` to determine if pasted data is `Code` or `Name`-only (via `bCode = tag.Equals("ISOCode")`). If `tag` is incorrect, data may be misassigned.
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- **Duplicate Code Handling**:
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Validation flags *duplicate code+name pairs* as errors, but allows duplicate codes with *different names*. This may be intentional (e.g., ISO codes can map to multiple names), but could be confusing.
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- **`OnChannelCodesCommitted` Logic Complexity**:
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The method builds multiple dictionaries (`lookup2`, `isoLookup`, `userLookup`) to avoid duplicates during batch commits. This is error-prone and duplicates logic in `Save()`.
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- **`ParseText` Delimiter Fallback**:
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Tries to split by `,`, then `\t`, then `;`. If none yield 2 tokens, the line is skipped. This may silently fail if data uses unexpected delimiters.
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- **`Validate` Ignores Blank Rows**:
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Blank rows (empty `Code`/`Name`) are skipped during validation. This is correct, but the logic is nested inside `CheckChannelCode`.
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- **No Undo/Revert**:
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Changes are published as `PageModifiedEvent(Status.Modified)` immediately on edit, but no mechanism to revert is visible.
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- **`ChannelCodesFunc` Usage Unclear**:
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`ChannelCodesFunc` is exposed but its usage (e.g., by `GetAllChannels`) is not shown in this file. Likely consumed externally.
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- **`UniqueISOCodesRequired` Flag**:
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The property exists but is never used in validation logic (despite its name). May be a future feature flag.
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- **`NotifySelectionChanged` Only Notifies When `ViewMode` Matches**:
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Selection change events are only published if the current `ViewMode` matches the selection type (ISO/User). This may cause inconsistent selection state if `ViewMode` changes after selection.
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- **No Null Checks on `View`**:
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`View.DataContext = this` assumes `View` is non-null, but no validation exists. |