AutoDarkMode/Windows-Auto-Night-Mode · warning · SwitchThemeException

Theme switching is unsuccessful: {result}

Error message

Theme switching is unsuccessful: {result}

What it means

Thrown in WallpaperPickerPage.DetectMonitorsAsync when the reply to Command.DetectMonitors is not StatusCode.Ok. Unlike errors 7-11 this is NOT RequestSwitch — it is the monitor-detection command. SwitchThemeException is (arguably mis-) reused here, carrying Source='WallpaperPickerPage'. The message becomes 'Theme switching is unsuccessful: {result}'. It is caught by the outer catch in DetectMonitorsAsync.

Source

Thrown at AutoDarkModeApp/Views/WallpaperPickerPage.xaml.cs:37

        InitializeComponent();
        Loaded += WallpaperPickerPage_Loaded;
    }

    private async void WallpaperPickerPage_Loaded(object sender, RoutedEventArgs e)
    {
        await DetectMonitorsAsync();
        LoadMonitors();
    }


    private async Task DetectMonitorsAsync()
    {
        try
        {
            string result = await MessageHandler.Client.SendMessageAndGetReplyAsync(Command.DetectMonitors);
            if (result != StatusCode.Ok)
            {
                throw new SwitchThemeException(result, "WallpaperPickerPage");
            }
            try
            {
                _builder.Load();
            }
            catch (Exception ex)
            {
                await _errorService.ShowErrorMessage(ex, App.MainWindow.Content.XamlRoot, "Constructor");
            }
        }
        catch (Exception ex)
        {
            await _errorService.ShowErrorMessage(ex, App.MainWindow.Content.XamlRoot, "Constructor");
        }
    }


    private void LoadMonitors()

View on GitHub (pinned to c15b28e921)

Solutions

1. Ensure AutoDarkModeSvc is running before opening the Wallpaper page.
2. Trigger a monitor re-detection after the display configuration stabilizes.
3. Check the service log for the monitor-detection failure reason.
4. Verify the display driver/OS is not mid mode-change (sleep, dock hot-plug).

// Confirm the service is up before navigating to the Wallpaper page
public static async Task<bool> IsServiceUpAsync()
{
    try { await MessageHandler.Client.SendMessageAndGetReplyAsync(Command.DetectMonitors); return true; }
    catch { return false; }
}

// DetectMonitorsAsync already wraps in try/catch routing to _errorService.
// Refactor async void -> Task so the caller can decide to retry or skip monitor load.

When it happens

Trigger: WallpaperPickerPage loads (OnNavigatedTo -> DetectMonitorsAsync). SendMessageAndGetReplyAsync(Command.DetectMonitors) returns != 'Ok'. The throw at line 37 is caught at the method's outer catch.

Common situations: Service cannot enumerate display monitors; monitor configuration changed during detection; service not running or returned Err; no reply within the default timeout.

Related errors

• Theme switching is unsuccessful: Couldn't clean up monitor l
• Theme switching is unsuccessful: {result}
• Could not add Auto Dark Mode to autostart
• Auto start task could not be set.
• Theme switching is unsuccessful: {result}

AI-assisted analysis of AutoDarkMode/Windows-Auto-Night-Mode@c15b28e921 (2026-08-13). Data as JSON: /api/errors/b07e761c2a37c1e9. Report an issue: GitHub.