Eliminate per-frame enum reflection/boxing in combo and property-grid enum rows

[Copilot]

Enum-backed combo paths were doing Enum.GetNames/Enum.GetValues in render-time code, causing repeated allocations every frame; Combo<TEnum> also used a non-generic Array path that introduced avoidable boxing. This change moves enum metadata to per-closed-type static caches and rewires affected call sites without changing public APIs or enum-selection behavior.

• Render-path allocation removal

  • Added internal EnumCache<TEnum> with static Values and Names, initialized once per enum type.
  • Replaced per-frame enum reflection calls in:
    • ImGuiWidgets.Combo<TEnum>
    • PropertyGrid.Enum<TEnum>
    • EnumCombo name enumeration path

• Boxing-free enum selection in Combo<TEnum>

  • Switched from non-generic Array/GetValue usage to typed array indexing.
  • Preserves existing selection semantics while removing the boxed GetValue conversion path.

• Behavior preserved for out-of-range enum values

  • Kept PropertyGrid.Enum<TEnum> guard (index >= 0 && index < values.Length) so cast/out-of-set values (including flags combinations) still render as “no selection” rather than faulting.

• Focused cache behavior coverage

  • Added tests asserting per-type cache reuse (same instance returned on repeated reads) for enum names/values paths.

internal static class EnumCache<TEnum> where TEnum : Enum
{
	internal static readonly TEnum[] Values = (TEnum[])Enum.GetValues(typeof(TEnum));
	internal static readonly string[] Names = Enum.GetNames(typeof(TEnum));
}

// Hot path now reads cached arrays:
TEnum[] values = EnumCache<TEnum>.Values;
string[] names = EnumCache<TEnum>.Names;
int index = Array.IndexOf(values, selectedValue);

• Fixes Enum combo rows reflect and allocate on every frame #385

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud