---
source_files:
  - DTS Viewer/DTS.Viewer/Resources/TranslateExtension.cs
  - DTS Viewer/DTS.Viewer/Resources/StringResources.Designer.cs
generated_at: "2026-04-16T11:23:12.329617+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "dbbc3094853fd65f"
---

# Documentation: DTS.Viewer.Resources Localization Module

## 1. Purpose

This module provides localization/internationalization support for the DTS Viewer WPF application. It enables XAML-based string lookup through a markup extension pattern, allowing UI elements to bind to localized resources declaratively. The `TranslateExtension` class serves as a bridge between XAML markup and the underlying `StringResources` resource manager, while `StringResources` provides strongly-typed, auto-generated access to localized strings stored in compiled resource files (.resx).

---

## 2. Public Interface

### `TranslateExtension` (Class)
**Namespace:** `DTS.Viewer`  
**Attributes:** `[MarkupExtensionReturnType(typeof(string))]`

A WPF markup extension that resolves localization keys to their corresponding string values at runtime.

| Member | Signature | Description |
|--------|-----------|-------------|
| Constructor | `TranslateExtension(string key)` | Initializes the extension with the resource key to look up. Stores the key in a readonly field `_key`. |
| `ProvideValue` | `public override object ProvideValue(IServiceProvider serviceProvider)` | Returns the localized string for the provided key. Returns `NotFound` constant if key is null/empty, or `NotFound + " " + _key` if the key is not found in resources. |
| `NotFound` | `private const string NotFound = "#stringnotfound#"` | Fallback string returned when a key is invalid or missing. |

---

### `StringResources` (Class)
**Namespace:** `DTS.Viewer.Resources`  
**Accessibility:** `internal`  
**Attributes:** `[GeneratedCode]`, `[DebuggerNonUserCode]`, `[CompilerGenerated]`

An auto-generated strongly-typed resource class providing access to localized strings.

| Member | Signature | Description |
|--------|-----------|-------------|
| `ResourceManager` | `internal static global::System.Resources.ResourceManager ResourceManager { get; }` | Lazily-initialized, cached `ResourceManager` instance for the `DTS.Viewer.Resources.StringResources` resource bundle. |
| `Culture` | `internal static global::System.Globalization.CultureInfo Culture { get; set; }` | Gets or sets the current UI culture for resource lookups. Overrides `Thread.CurrentUICulture` for this resource class. |

**Localized String Properties (all `internal static string`):**

| Property | Default Value (from comments) |
|----------|-------------------------------|
| `ChartOptionsHeader` | "Chart Options" |
| `GraphsDefaultTitle` | "Graphs " |
| `ModificationsHeader` | "Modify" |
| `SavePDFError` | "Error occurred saving chart to PDF" |
| `SavePDFSuccess` | "Chart saved succesfully as {0}{1} and {2}{3}" |
| `SettingsTitle` | "Settings" |
| `TestIDsDefaultTitle` | "Test IDs" |
| `TestsDefaultTitle` | "Tests " |

---

## 3. Invariants

1. **Key immutability:** The `_key` field in `TranslateExtension` is `readonly` and set only at construction time.

2. **Null safety:** `ProvideValue` will never return null. It returns either the localized string, `NotFound` (for null/empty keys), or `NotFound + " " + _key` (for missing keys).

3. **ResourceManager singleton:** The `ResourceManager` property uses a check-then-create pattern with a temporary variable to ensure thread-safe lazy initialization.

4. **Resource name mapping:** The `ResourceManager` is initialized with the base name `"DTS.Viewer.Resources.StringResources"`, which must match the embedded resource path.

5. **Culture fallback:** If `Culture` property is not explicitly set (`resourceCulture` is null), `ResourceManager.GetString` uses the current thread's `CurrentUICulture`.

---

## 4. Dependencies

### This module depends on:
- `System` (core .NET types)
- `System.Windows.Markup` - for `MarkupExtension` base class and `MarkupExtensionReturnTypeAttribute`
- `System.Resources` - for `ResourceManager` class
- `System.Globalization` - for `CultureInfo` class
- `System.CodeDom.Compiler`, `System.Diagnostics`, `System.Runtime.CompilerServices` - for auto-generated attributes
- **Resource files (.resx)** - The actual localized string data backing `StringResources` (not included in source, but implied by the designer file)

### What depends on this module:
- **XAML files in DTS.Viewer** - Use `{x:Static res:StringResources.PropertyName}` or `{local:Translate KeyName}` syntax for localized strings
- **PDF export functionality** - Uses `SavePDFSuccess` and `SavePDFError` strings
- **Chart/Graph UI components** - Use `ChartOptionsHeader`, `GraphsDefaultTitle`, `ModificationsHeader`
- **Settings UI** - Uses `SettingsTitle`
- **Test-related UI** - Uses `TestIDsDefaultTitle`, `TestsDefaultTitle`

---

## 5. Gotchas

1. **`StringResources` is `internal`:** The class cannot be accessed from outside the `DTS.Viewer` assembly. External libraries cannot directly use these resources.

2. **Missing key behavior:** Missing localization keys do not throw exceptions. Instead, they return `"#stringnotfound# {key}"`, which may appear in production UI if resources are misconfigured. This is intentional fallback behavior but could mask configuration errors.

3. **Typo in resource string:** The `SavePDFSuccess` resource contains "succesfully" (missing one 'l') per the source comments. This typo originates from the .resx file, not the generated code.

4. **Trailing spaces:** `GraphsDefaultTitle` and `TestsDefaultTitle` have trailing spaces in their default values ("Graphs " and "Tests "). This may be intentional for UI layout but could cause issues if trimmed unexpectedly.

5. **Format string dependency:** `SavePDFSuccess` expects 4 format arguments (`{0}{1} and {2}{3}`). Callers must provide exactly 4 arguments or a `FormatException` will occur at runtime.

6. **Auto-generated file warning:** `StringResources.Designer.cs` is regenerated by tooling. Manual edits will be lost. The underlying `.resx` file is the source of truth.