[Windows] Fix SearchBar icon not updating on runtime theme changes

[Copilot]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Description

Fixes an issue where the SearchBar's search icon does not change color when switching themes at runtime on Windows.

Problem

The SearchBar uses an AutoSuggestBox with a SymbolIcon as the QueryIcon on Windows. This icon was created once during platform view creation and never updated when the application theme changed, causing it to retain its original color scheme even after switching between light and dark themes.

Solution

Added theme change detection to the SearchBarHandler on Windows:

1. Subscribe to Application.Current.RequestedThemeChanged event in ConnectHandler
2. Recreate the QueryIcon when theme changes occur to pick up new theme colors
3. Properly unsubscribe in DisconnectHandler to prevent memory leaks

Code Changes

// Subscribe to theme changes
if (Application.Current is not null)
    Application.Current.RequestedThemeChanged += OnAppThemeChanged;

// Handle theme changes by recreating the icon
void OnAppThemeChanged(object? sender, AppThemeChangedEventArgs e)
{
    UpdateQueryIcon();
}

void UpdateQueryIcon()
{
    if (PlatformView is not null)
    {
        // Recreate QueryIcon to inherit current theme colors
        PlatformView.QueryIcon = new SymbolIcon(Symbol.Find);
    }
}

Testing

To test the fix:

1. Create a MAUI app with a SearchBar
2. Switch theme at runtime: Application.Current.UserAppTheme = AppTheme.Dark
3. Verify the search icon color changes to match the dark theme
4. Switch back to light theme and verify the icon reverts appropriately

Impact

• Platforms affected: Windows only (platform-specific issue)
• Breaking changes: None
• API changes: None
• Code impact: Minimal (~15 lines added to Windows SearchBar handler)

Fixes #15.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

• 4vyvsblobprodcus361.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• 4zjvsblobprodcus390.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• gervsblobprodcus329.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• jd4vsblobprodcus366.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• kxqvsblobprodcus376.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• o3svsblobprodcus318.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• rcxvsblobprodcus328.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)
• tphvsblobprodcus375.vsblob.vsassets.io
  • Triggering command: dotnet test src/Controls/tests/DeviceTests/ --filter SearchBarTests --configuration Debug --verbosity minimal (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to my firewall allow list

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[devanathan-vaithiyanathan]

@copilot , In the handler, when accessing the Application, it refers to the native Application. I need to get the .NET MAUI theme, and when the theme changes, I want to update the search icon color based on the current theme.

[Copilot]

You're absolutely right! I was accessing the native Windows Application instead of the MAUI Application. I've updated the code to use Microsoft.Maui.Controls.Application.Current which properly accesses the .NET MAUI theme system. This ensures the SearchBar icon updates correctly when the MAUI theme changes at runtime. Fixed in commit 34edd4b.