Search functionality on WPF, WinUI, Maui is shared

[OAzmitia]

Description

To improve the search functionality on WPF and WinUI we abstracted the Maui search functionality to be shared between all projects. Previously, a search "dynamic gallery" would attempt to match the full string into a name or description and return no results. This PR fixes that.

Type of change

• Sample viewer enhancement
  Changes are visible on WPF and WinUI, although underlying changes apply to all projects.

Implementation:

1. Abstract the search functionality in the Maui project into a shared SearchEngine class in the Shared project.
2. Added models to profile a sample into keywords and hit score
3. Remove concrete references to the SearchResultViewModel and created a model to reflect the results.
4. Added SearchEngine to SampleManager class.
5. Call SearchEngine from Maui, WPF, WinUI.

Platforms tested on

• WPF .NET 8
• WinUI
• MAUI WinUI
• MAUI Android
• MAUI iOS
• MAUI MacCatalyst

Checklist

• Self-review of changes
• All changes work as expected on all affected platforms
• There are no warnings related to changes
• Code is commented and follows .NET conventions and standards
• Codemaid and XAML styler extensions have been run on every changed file
• No unrelated changes have been made to any other code or project files

[OAzmitia]

This file is not new code, it just got moved from inside SearchViewModel

[OAzmitia]

This was moved to a new file

[OAzmitia]

Most of the code in this file was moved from Maui search implementation, the changes happened under the SearchEngine constructor and Search method. Extra focus on those methods would cover 90% of the changes.

[praveenaak]

In the previous version of the WPF/WinUI, searching for "Display local scene" returned the expected sample as the top result.

After these changes, the same query returns a large number of results with the intended sample buried near the bottom of the list.

The same search query on MAUI shows the intended sample as the top result.

[OAzmitia]

In reply to this 👆 comment.

This issue concerns how search results are presented in .NET MAUI compared to WinUI/WPF applications.

Current behavior:

• MAUI displays search results in a flat list, making it easy to sort results by descending match score.
• WinUI/WPF displays search results grouped by category in a tree control, preserving category organization.

The search implementation is now shared across all platforms and provides a match score for each result. However, because WinUI/WPF presents results in a hierarchical tree structure, it is not straightforward to surface the highest scoring matches at the top without modifying the existing UI.

Possible Approaches

Option	Description	Effort
Display results in a flat list for WinUI/WPF	Introduce a dedicated list control for search results, reusing the existing item template. Results would be displayed in a single list sorted by descending match score, providing behavior consistent with MAUI.	Medium
Keep the current grouped view	Ignore match scores for presentation purposes and continue displaying search results grouped by category in the existing tree structure.	None (already done)
Add a "Top Results" section	Add a new top-level tree node named Top Results that contains the highest scoring matches. Remaining results would continue to be displayed within their existing category groups.	Medium

Discussion

The primary consideration is whether consistency of result ranking across platforms is more important than preserving the existing categorized navigation experience on WinUI/WPF.

The flat list approach provides the most consistent ranking experience with MAUI, while the Top Results approach attempts to balance relevance-based ranking with the existing grouped presentation model.

[praveenaak]

Opting for "Display results in a flat list for WinUI/WPF" would also fix this issue.

[OAzmitia]

Updated the code to show results with highest score

WPF/WinUI Results	Maui Results

[imalcolm1]

Looks good, thanks a bunch for implementing this!