SearchableDropdown attribute

[Luanrobs]

Hi!
I’d like to propose the idea of adding searchable dropdowns to TriInspector.

I’m not sure what the best approach would be for TriInspector:

1. Introducing a dedicated attribute, something like SearchableDropdown
2. Making searchable dropdowns the default behavior whenever a dropdown exceeds a certain size
3. Creating a shared utility that standardizes the implementation of searchable dropdowns for all TriInspector attributes.
   In this case, existing attributes like [Dropdown] could opt-in to the feature, and new attributes (including the ones in my PR #206) could reuse the same utility. It could even support an optional parameter such as:
   [Dropdown(searchable: false)].

This feature would be especially useful for existing attributes like [Dropdown], and also for the two new attributes I introduced in my open PR #206 — [AnimatorParameter] and [MaterialProperty] — both of which often deal with long, hard-to-navigate lists. A searchable option would make them far more convenient and user-friendly.

Here are examples from other tools that inspired this suggestion:

Unity-Editor-Toolbox [SearchableEnum] attribute

[SearchableEnum]
public KeyCode enumSearch;

MyBox [SearchableEnum] attribute

[vanifatovvlad]

Hi!
That's a great idea.

Tri-Inspector has a reusable element that displays a drop-down list:
https://github.com/codewriter-packages/Tri-Inspector/blob/main/Editor/Elements/TriDropdownElement.cs
This implementation is also optimized to avoid making unnecessary calls to valuesGetter method.

At the moment it is already in use in:

• AssetDropDownAttribute - https://github.com/codewriter-packages/Tri-Inspector/blob/main/Editor.Extras/Drawers/AssetDropdownDrawer.cs#L34
• DropdownAttribute - https://github.com/codewriter-packages/Tri-Inspector/blob/main/Editor.Extras/Drawers/DropdownDrawer.cs#L29

It displays a regular dropdown only, but I think it can be extended to display a searchable list too.

Then it would be possible to add optional Searchable property to all dropdown attributes:

public class DropdownAttribute : Attribute {
    public bool Searchable { get; set; }
}

[Dropdown(... , Searchable = true)]
public string s;

[AssetDropdown(..., Searchable = true)]
public string s;

and so on

As for implementation of a dropdown with search, Tri-Inspector has an implementation that can be used as a reference
https://github.com/codewriter-packages/Tri-Inspector/blob/main/Editor/Utilities/TriManagedReferenceGui.cs#L23