This module is part of the Unity Essentials ecosystem and follows the same lightweight, editor-first approach. Unity Essentials is a lightweight, modular set of editor utilities and helpers that streamline Unity development. It focuses on clean, dependency-free tools that work well together.

All utilities are under the UnityEssentials namespace.

using UnityEssentials;

Install the Unity Essentials entry package via Unity's Package Manager, then install modules from the Tools menu.

• Add the entry package (via Git URL)

  • Window → Package Manager
  • "+" → "Add package from git URL…"
  • Paste: https://github.com/EggyStudio/UnityEssentials.git

• Install or update Unity Essentials packages

  • Tools → Install & Update UnityEssentials
  • Install all or select individual modules; run again anytime to update

Quick overview: Drop-in MonoBehaviours for common UI Toolkit tasks - event routing, OnValueChanged handlers, label/background setters, and display toggling - powered by the UI Element Linker. No custom editor code required.

This module bundles small, focused behaviours that work with the Element Linker to control and listen to UI Toolkit elements without boilerplate. Add them to a GameObject alongside a UIElementLink or UIElementQuery to forward click/key/pointer/focus events, react to value changes in common controls, set labels and backgrounds, and toggle display - all in Edit or Play Mode and across one or many linked elements.

• UI Element linking (via Element Linker)
  • Bind one or many VisualElements from a UIDocument using UIElementLink (single) or UIElementQuery (query by name/class/type)
  • Components work on the linked set; no manual root.Q() in your scripts
• Components included
  • UI Event Handler (UIEventHandler)
    • UnityEvents for: Click, Key (Down/Up with KeyCode), Pointer (Down/Up/Enter/Leave with Vector3), Focus/Blur
    • Also exposes typed event payloads (ClickEvent, KeyDownEvent, etc.) if you need the full UI Toolkit event
    • Registers only the callbacks you’ve assigned → minimal overhead; unregisters on disable/destroy
  • UI On Value Changed Handler (UIOnValueChangedEventHandler)
    • Routes ChangeEvent<T> for supported elements: TextField, Label, Slider, SliderInt, DropdownField, Foldout
    • Two UnityEvents per type: one with the new value (e.g., float, string, bool) and one with the full ChangeEvent<T>
    • Clean inspector using [ShowIf] to show only relevant sections per linked element type
  • UI Set Label (UISetLabel)
    • Sets the Label.text of all linked Label elements
    • Simple LabelText property updates the UI immediately
  • UI Set Background (UISetBackground)
    • Sets background color and/or texture on all linked elements (uses UI Toolkit Extensions)
  • UI Display Toggle (UIDisplayToggle)
    • Shows/hides linked elements using display: flex/none
    • Optional "Display On Start" and a public Toggle() method
• Works in Edit Mode (where applicable)
  • UIEventHandler and UIOnValueChangedEventHandler are [ExecuteAlways] so you can test from the editor

• Unity Editor 6000.0+ (Editor/Runtime UI Toolkit)
• A UIDocument in your scene
• Dependencies (Unity Essentials modules)
  • UI Toolkit Element Linker: provides UIElementLink, UIElementQuery, and UIScriptComponentBase
  • UI Toolkit Extensions: color/image helpers like SetBackgroundImage, SetBackgroundColor
  • Editor Attributes – ShowIf: attributes used by the value-changed handler’s inspector ([ShowIf], [ShowIfNot], [Info])

Tip: If a component seems inactive, make sure the GameObject also has either a UIElementLink or UIElementQuery set up and points at existing elements in the UIDocument.

1. Link elements

• Add UIElementLink to bind a single VisualElement (drag from a UI Builder-referenced UIDocument or query in code)
• Or add UIElementQuery to bind multiple elements by name/class/type
• Keep the linker and the component on the same GameObject

2. Add a component

• Choose one or more of:
  • UIEventHandler
  • UIOnValueChangedEventHandler
  • UISetLabel
  • UISetBackground
  • UIDisplayToggle

3. Configure and wire events

• For event components, expand the relevant UnityEvent and hook your methods
• For setters, edit LabelText, BackgroundColor, BackgroundTexture, or "Display On Start"

Examples

• Button click

// On a GameObject with UIElementLink -> (your Button)
// Add UIEventHandler and wire in Inspector, or do it from code:
public class ButtonActions : MonoBehaviour
{
    public void OnClicked() => Debug.Log("Button clicked");
}

• Slider value changed

// On a GameObject with UIElementQuery -> (your Slider)
// Add UIOnValueChangedEventHandler; in the Inspector, wire SliderEvents.OnSliderChanged(float)
public class SliderActions : MonoBehaviour
{
    public void OnValue(float v) => Debug.Log($"Slider = {v}");
}

• Set label text from code

var labelSetter = GetComponent<UISetLabel>();
labelSetter.LabelText = "Hello UI Toolkit";

• Toggle display at runtime

GetComponent<UIDisplayToggle>().Toggle();

• Linking and base class
  • UIScriptComponentBase looks for UIElementLink or UIElementQuery on the same GameObject and caches:
    • Document (the UIDocument), LinkedElements (array), and Type (UIElementType)
  • Helper IterateLinkedElements(...) is used by all components to apply changes to every linked element
• Event components
  • Register callbacks on OnEnable only for events that have listeners; unregister on OnDisable/OnDestroy
  • UI Toolkit events are forwarded both as simplified values and as full event structs
• Setters
  • UISetLabel updates Label.text on Start and whenever LabelText changes
  • UISetBackground uses extension methods to apply color/texture on OnEnable
• Display toggle
  • UIDisplayToggle flips style.display between Flex and None; provides SetEnabled(bool) and Toggle()

• Supported value-changed elements: TextField, Label, Slider, SliderInt, DropdownField, Foldout
  • Other controls aren’t wired by default; extend UIOnValueChangedEventHandler if needed
• Requires a valid link
  • If LinkedElements is empty or the query doesn’t match, components do nothing safely
• Edit Mode behavior
  • UIEventHandler and UIOnValueChangedEventHandler are [ExecuteAlways]; avoid heavy listeners that should only run in Play Mode
• Background texture/color
  • If BackgroundTexture is null, only color is applied
• UnityEvents
  • Invoked on the main thread; ensure subscribers are lightweight to avoid frame hitches

• Runtime/UIEventHandler.cs – Click/Key/Pointer/Focus event routing
• Runtime/UIOnValueChangedEventHandler.cs – Value-changed routing for common elements
• Runtime/UISetLabel.cs – Sets Label.text for linked labels
• Runtime/UISetBackground.cs – Sets background color/texture for linked elements
• Runtime/UIDisplayToggle.cs – Show/hide (display) toggling with optional start state
• Runtime/UnityEssentials.UIToolkitScriptComponents.asmdef – Runtime assembly definition

unity, ui toolkit, visualelement, events, value-changed, label, background, toggle, script components, runtime