Command events

Command events are sent to allow the Unity Editor to forward top-level menu actions to the Editor UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary, as well as their equivalent keyboard shortcuts.

The following are the available commands:

• Copy
• Cut
• Paste
• Delete
• SoftDelete
• Duplicate
• FrameSelected
• FrameSelectedWithLock
• SelectAll
• Find
• FocusProjectWindow

Unique properties

target: The element with keyboard focus. This value is null if no element has focus.

commandName: The command to validate or execute.

Event List

ValidateCommandEvent

The ValidateCommandEvent event asks an EditorWindow if it can execute a command. For example, the Editor can enable or disable a menu item based on the results from the validation command event.

To verify if the Editor can execute a command:

1. Register a callback for ValidateCommandEvent.
2. Test the commandName property of the event.
3. Call the Event.StopPropogation() method on the event if the command can be executed.

ExecuteCommandEvent

The ExecuteCommandEvent event asks an Editor Window to execute a command.

Even if this event follows a validation event, it’s best practice to ensure the action is possible first, independently of any previous validation.

To respond to the command:

1. Register a callback for ExecuteCommandEvent.
2. Test the commandName property of the event.
3. Call the Event.StopPropogation() method on the event before executing the actual logic of the command, so the Editor knows that the comment has been executed.

Example

The following example uses command events to support copy and paste in a custom Editor Window. The example displays a list of fruits in a custom Editor window. Users can use keyboard shortcuts to copy and paste any fruits.

using System;
using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

public class CopyPasteExample : EditorWindow
{
    [MenuItem("Window/UI Toolkit Examples/CopyPasteExample")]
    public static void Show()
    {
        GetWindow<CopyPasteExample>();
    }

    readonly List<string> fruits = new ()
    {
        "Banana",
        "Apple",
        "Lime",
        "Orange"
    };
    
    ListView m_ListView;

    public void CreateGUI()
    {
        Func<VisualElement> makeItem = () => new Label();

        Action<VisualElement, int> bindItem = (e, i) => (e as Label).text = fruits[i];

        m_ListView = new ListView();
        m_ListView.makeItem = makeItem;
        m_ListView.bindItem = bindItem;
        m_ListView.itemsSource = fruits;
        m_ListView.selectionType = SelectionType.Single;
        
        m_ListView.RegisterCallback<ValidateCommandEvent>(OnValidateCommand);
        m_ListView.RegisterCallback<ExecuteCommandEvent>(OnExecuteCommand);
        
        rootVisualElement.Add(m_ListView);
    }

    void OnExecuteCommand(ExecuteCommandEvent evt)
    {
        if (evt.commandName == "Copy" && m_ListView.selectedIndices.Count() > 0)
        {
            EditorGUIUtility.systemCopyBuffer = fruits[m_ListView.selectedIndex];
            evt.StopPropagation();
        }
        else if (evt.commandName == "Paste" && !string.IsNullOrEmpty(EditorGUIUtility.systemCopyBuffer))
        {
            fruits.Add(EditorGUIUtility.systemCopyBuffer);
            m_ListView.RefreshItems();
            evt.StopPropagation();
        }
    }

    void OnValidateCommand(ValidateCommandEvent evt)
    {
        if (evt.commandName == "Copy" && m_ListView.selectedIndices.Count() > 0)
        {
            evt.StopPropagation();
        }
        else if (evt.commandName == "Paste" && !string.IsNullOrEmpty(EditorGUIUtility.systemCopyBuffer))
        {
            evt.StopPropagation();
        }
    }
}