Service Interfaces

Service interfaces provide business logic and system functionality, including settings management, search, window management, tray service, and localization.

ISettingsService

Application settings service for loading and saving settings.

Interface Definition

csharp

namespace DesktopMemo.Core.Contracts;

/// <summary>
/// Provides interfaces for loading and saving application settings.
/// </summary>
public interface ISettingsService
{
    Task<WindowSettings> LoadAsync(CancellationToken cancellationToken = default);
    Task SaveAsync(WindowSettings settings, CancellationToken cancellationToken = default);
}

Method Details

LoadAsync

Loads application settings.

Signature:

csharp

Task<WindowSettings> LoadAsync(CancellationToken cancellationToken = default)

Returns:

Task<WindowSettings> - settings loaded from disk; returns defaults if the file does not exist

Example:

csharp

var settings = await _settingsService.LoadAsync();
Console.WriteLine($"Window size: {settings.Width}x{settings.Height}");
Console.WriteLine($"Transparency: {settings.Transparency}");

Notes:

If the settings file does not exist, returns WindowSettings.Default
If the file is corrupted, tries to restore from backup
On failure, logs the error and returns default settings

SaveAsync

Saves application settings.

Signature:

csharp

Task SaveAsync(WindowSettings settings, CancellationToken cancellationToken = default)

Parameters:

settings - settings to save

Example:

csharp

var newSettings = currentSettings.WithSize(1200, 800);
await _settingsService.SaveAsync(newSettings);

Notes:

Uses atomic save: write to a temp file, then replace the original
Creates a backup file before overwriting
Stored in JSON format

Paths:

Main file: .memodata/settings.json
Backup file: .memodata/settings.json.backup

Best practice (atomic update):

csharp

try
{
    var newSettings = currentSettings with { Transparency = 0.2 };
    await _settingsService.SaveAsync(newSettings); // persist first
    CurrentSettings = newSettings; // update in-memory state only on success
}
catch (Exception ex)
{
    Debug.WriteLine($"Failed to save settings: {ex}");
}

IMemoSearchService

Memo search service, providing find and replace.

Interface Definition

csharp

namespace DesktopMemo.Core.Contracts;

public interface IMemoSearchService
{
    IEnumerable<SearchMatch> FindMatches(string text, string keyword,
        bool caseSensitive = false, bool useRegex = false);

    string Replace(string text, string keyword, string replacement,
        bool caseSensitive = false, bool useRegex = false);
}

public sealed record SearchMatch(int Index, int Length);

Method Details

FindMatches

Finds all matches in a text.

Signature:

csharp

IEnumerable<SearchMatch> FindMatches(string text, string keyword,
    bool caseSensitive = false, bool useRegex = false)

Parameters:

text - input text
keyword - search keyword or regex pattern
caseSensitive - case-sensitive match (default: false)
useRegex - treat keyword as regex (default: false)

Returns:

IEnumerable<SearchMatch> - match list containing index and length

Example:

csharp

var text = "Hello World, hello universe";
var matches = _searchService.FindMatches(text, "hello", caseSensitive: false);

foreach (var match in matches)
{
    Console.WriteLine($"Match: index={match.Index}, length={match.Length}");
    var matchedText = text.Substring(match.Index, match.Length);
    Console.WriteLine($"Text: {matchedText}");
}

Regex example:

csharp

var matches = _searchService.FindMatches(
    text,
    @"\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b",
    useRegex: true
);

Replace

Replaces all matches.

Signature:

csharp

string Replace(string text, string keyword, string replacement,
    bool caseSensitive = false, bool useRegex = false)

Parameters:

text - original text
keyword - keyword or regex pattern
replacement - replacement text
caseSensitive - case-sensitive match
useRegex - regex mode

Returns:

string - replaced text

Example:

csharp

var text = "Hello World, hello universe";
var result = _searchService.Replace(text, "hello", "Hi", caseSensitive: false);
Console.WriteLine(result);

Regex replacement example:

csharp

var result = _searchService.Replace(
    "Version 2.3.0 released on 2025-11-15",
    @"\d+",
    "[NUM]",
    useRegex: true
);

IWindowService

Window management service: topmost mode, transparency, click-through, positioning, and tray integration.

Interface Definition

csharp

namespace DesktopMemo.Core.Contracts;

public enum TopmostMode
{
    Normal,     // normal mode
    Desktop,    // desktop-layer topmost
    Always      // always on top
}

public interface IWindowService
{
    void SetTopmostMode(TopmostMode mode);
    TopmostMode GetCurrentTopmostMode();
    void SetClickThrough(bool enabled);
    bool IsClickThroughEnabled { get; }
    void SetWindowPosition(double x, double y);
    (double X, double Y) GetWindowPosition();
    void MoveToPresetPosition(string position);
    void SetWindowOpacity(double opacity);
    double GetWindowOpacity();
    void PlayFadeInAnimation();
    void ToggleWindowVisibility();
    void MinimizeToTray();
    void RestoreFromTray();
}

Method Details

SetTopmostMode

Sets window topmost mode.

Signature:

csharp

void SetTopmostMode(TopmostMode mode)

Parameters:

mode - Normal / Desktop / Always

Example:

csharp

_windowService.SetTopmostMode(TopmostMode.Always);
_windowService.SetTopmostMode(TopmostMode.Normal);

Notes:

Desktop uses Win32 API to place the window above desktop icons
Always uses WPF Topmost
Tray menu state should be updated when switching modes

SetClickThrough

Enables/disables click-through.

Signature:

csharp

void SetClickThrough(bool enabled)

Example:

csharp

_windowService.SetClickThrough(true);
_windowService.SetClickThrough(false);

Notes:

Clicks pass through the window to the underlying applications
Implemented by setting Win32 extended style WS_EX_TRANSPARENT
Tray menu can still control the window while click-through is enabled

SetWindowPosition

Sets window position (screen coordinates).

Signature:

csharp

void SetWindowPosition(double x, double y)

Example:

csharp

_windowService.SetWindowPosition(0, 0);

var screenWidth = SystemParameters.PrimaryScreenWidth;
var screenHeight = SystemParameters.PrimaryScreenHeight;
_windowService.SetWindowPosition(
    (screenWidth - windowWidth) / 2,
    (screenHeight - windowHeight) / 2
);

MoveToPresetPosition

Moves to a preset position.

Signature:

csharp

void MoveToPresetPosition(string position)

Allowed values:

"top-left", "top-right", "bottom-left", "bottom-right", "center"

Example:

csharp

_windowService.MoveToPresetPosition("bottom-right");
_windowService.MoveToPresetPosition("center");

SetWindowOpacity

Sets window opacity.

Signature:

csharp

void SetWindowOpacity(double opacity)

Parameters:

opacity - 0.0 to 1.0 (app limits to 0.05–0.4)

Example:

csharp

_windowService.SetWindowOpacity(0.2);

using DesktopMemo.Core.Constants;
_windowService.SetWindowOpacity(WindowConstants.DEFAULT_TRANSPARENCY);

Notes:

Prefer WindowConstants and TransparencyHelper for consistent opacity management

MinimizeToTray / RestoreFromTray

Example:

csharp

_windowService.MinimizeToTray();
_windowService.RestoreFromTray();

ITrayService

System tray service for tray icon and menus.

Interface Definition

csharp

namespace DesktopMemo.Core.Contracts;

public interface ITrayService : IDisposable
{
    // Events
    event EventHandler? TrayIconDoubleClick;
    event EventHandler? ShowHideWindowClick;
    event EventHandler? NewMemoClick;
    event EventHandler? SettingsClick;
    event EventHandler? ExitClick;
    event EventHandler<string>? MoveToPresetClick;
    event EventHandler? RememberPositionClick;
    event EventHandler? RestorePositionClick;
    event EventHandler<bool>? ClickThroughToggleClick;
    event EventHandler<TopmostMode>? TopmostModeChangeClick;

    // Methods
    void Initialize();
    void Show();
    void Hide();
    void ShowBalloonTip(string title, string text, int timeout = 2000);
    void UpdateText(string text);
    void UpdateTopmostState(TopmostMode mode);
    void UpdateClickThroughState(bool enabled);
    void UpdateMenuTexts(Func<string, string> getLocalizedString);
}

Method Details

Initialize

Initializes the tray icon and menu.

Example:

csharp

_trayService.Initialize();
_trayService.Show();

ShowBalloonTip

Shows a balloon tip.

Signature:

csharp

void ShowBalloonTip(string title, string text, int timeout = 2000)

Parameters:

title - title
text - message
timeout - milliseconds (default: 2000)

Example:

csharp

_trayService.ShowBalloonTip("Saved", "Memo has been saved", 3000);

UpdateMenuTexts

Updates tray menu texts (for language switching).

Example:

csharp

_trayService.UpdateMenuTexts(key => _localizationService[key]);

ILocalizationService

Localization service.

Interface Definition

csharp

namespace DesktopMemo.Core.Contracts;

public interface ILocalizationService
{
    string this[string key] { get; }
    CultureInfo CurrentCulture { get; }
    void ChangeLanguage(string cultureName);
    IEnumerable<CultureInfo> GetSupportedLanguages();
    event EventHandler<LanguageChangedEventArgs>? LanguageChanged;
}

Method Details

Get localized strings

Example:

csharp

var saveText = _localizationService["Save"];
var cancelText = _localizationService["Cancel"];

// In XAML:
// <TextBlock Text="{loc:Localize Save}" />

ChangeLanguage

Switches language.

Signature:

csharp

void ChangeLanguage(string cultureName)

Common values:

"zh-CN" - Simplified Chinese
"en-US" - English
"zh-TW" - Traditional Chinese
"ja-JP" - Japanese
"ko-KR" - Korean

Example:

csharp

_localizationService.ChangeLanguage("en-US");

_localizationService.LanguageChanged += (s, e) =>
{
    Console.WriteLine($"Language switched: {e.OldCulture} -> {e.NewCulture}");
    _trayService.UpdateMenuTexts(key => _localizationService[key]);
};

GetSupportedLanguages

Returns supported languages.

Example:

csharp

var languages = _localizationService.GetSupportedLanguages();
foreach (var lang in languages)
{
    Console.WriteLine($"{lang.DisplayName} ({lang.Name})");
}

ILogService

Logging service.

Interface Definition

csharp

namespace DesktopMemo.Core.Contracts;

public interface ILogService
{
    void Log(string message, LogLevel level = LogLevel.Info);
    Task<IEnumerable<LogEntry>> GetLogsAsync(int count = 100);
    Task ClearLogsAsync();
}

Method Details

Log

Example:

csharp

_logService.Log("App started", LogLevel.Info);
_logService.Log("Save failed", LogLevel.Error);

Implementations

JsonSettingsService

Location: DesktopMemo.Infrastructure.Services
Uses JSON to store settings
Supports backup and restore

MemoSearchService

Location: DesktopMemo.Infrastructure.Services
Supports plain text and regex search
Case-insensitive option

WindowService

Location: DesktopMemo.Infrastructure.Services
Uses Win32 APIs to control the window
Supports multiple topmost modes and transparency

TrayService

Location: DesktopMemo.Infrastructure.Services
Uses WinForms NotifyIcon
Provides a rich tray menu

LocalizationService

Location: DesktopMemo.App.Localization
Uses resource files
Supports dynamic language switching

FileLogService

Location: DesktopMemo.Infrastructure.Services
Logs stored under .memodata/.logs/
Rotates by date automatically

Best Practices

1. Atomic settings saves

csharp

try
{
    var newSettings = currentSettings with { Theme = AppTheme.Dark };
    await _settingsService.SaveAsync(newSettings);
    CurrentSettings = newSettings;
}
catch (Exception ex)
{
    Debug.WriteLine($"Save failed: {ex}");
}

2. Using the search service

csharp

var matches = _searchService.FindMatches(content, keyword);
foreach (var match in matches)
{
    HighlightText(match.Index, match.Length);
}

3. Coordinating window and settings state

csharp

_windowService.SetTopmostMode(TopmostMode.Always);
_trayService.UpdateTopmostState(TopmostMode.Always);

var newSettings = settings with { IsTopMost = true, IsDesktopMode = false };
await _settingsService.SaveAsync(newSettings);

Last Updated: 2025-11-15

Service Interfaces ​

ISettingsService ​

Interface Definition ​

Method Details ​

LoadAsync ​

SaveAsync ​

IMemoSearchService ​

Interface Definition ​

Method Details ​

FindMatches ​

Replace ​

IWindowService ​

Interface Definition ​

Method Details ​

SetTopmostMode ​

SetClickThrough ​

SetWindowPosition ​

MoveToPresetPosition ​

SetWindowOpacity ​

MinimizeToTray / RestoreFromTray ​

ITrayService ​

Interface Definition ​

Method Details ​

Initialize ​

ShowBalloonTip ​

UpdateMenuTexts ​

ILocalizationService ​

Interface Definition ​

Method Details ​

Get localized strings ​

ChangeLanguage ​

GetSupportedLanguages ​

ILogService ​

Interface Definition ​

Method Details ​

Log ​

Implementations ​

JsonSettingsService ​

MemoSearchService ​

WindowService ​

TrayService ​

LocalizationService ​

FileLogService ​

Best Practices ​

1. Atomic settings saves ​

2. Using the search service ​

3. Coordinating window and settings state ​

Related Docs ​

Service Interfaces

ISettingsService

Interface Definition

Method Details

LoadAsync

SaveAsync

IMemoSearchService

Interface Definition

Method Details

FindMatches

Replace

IWindowService

Interface Definition

Method Details

SetTopmostMode

SetClickThrough

SetWindowPosition

MoveToPresetPosition

SetWindowOpacity

MinimizeToTray / RestoreFromTray

ITrayService

Interface Definition

Method Details

Initialize

ShowBalloonTip

UpdateMenuTexts

ILocalizationService

Interface Definition

Method Details

Get localized strings

ChangeLanguage

GetSupportedLanguages

ILogService

Interface Definition

Method Details

Log

Implementations

JsonSettingsService

MemoSearchService

WindowService

TrayService

LocalizationService

FileLogService

Best Practices

1. Atomic settings saves

2. Using the search service

3. Coordinating window and settings state

Related Docs