Event.Use

描述

使用该事件。

在您已使用了一个事件时调用此方法。该事件的类型将被设置为 EventType.Used，这会导致其他 GUI 元素忽略此类型。

不应使用类型为 EventType.Repaint 和 EventType.Layout 的事件。 尝试在此类事件上调用此方法将会发出警告。

The following example demonstrates how events are consumed and used up. Copy this code into a script, and open the Example Window this sample creates from the Window menu.

using UnityEditor;
using UnityEngine;

public class ExampleWindow : EditorWindow
{
    [MenuItem("Window/Show Example Window")]
    public static void ShowWindow()
    {
        GetWindow(typeof(ExampleWindow));
    }

    private void OnGUI()
    {
        if (Event.current.type == EventType.MouseDown && Event.current.button == 0)
        {
            Debug.Log("Left clicked at: " + Event.current.mousePosition);
            // This if statement Uses up the current MouseDown event so that
            // subsequent code or GUI elements ignore this MouseDown event. 
            Event.current.Use();
        }

        // This if statement does not check Event.current.button, but it only triggers
        // when Event.current.button is not 0 because the previous if statement will
        // Use up the MouseDown event if it is. 
        if (Event.current.type == EventType.MouseDown) 
        {
            Debug.Log("This only prints when we right click!");
            Event.current.Use();
        }
    }
}

The following example demonstrates how handles such as Handles.PositionHandle and Handles.FreeMoveHandle might use events.

using UnityEditor;
using UnityEngine;

public static class CustomHandle
{
    public static bool DoHandle(Vector3 worldpos, float size, float pickSize)
    {
        int id = GUIUtility.GetControlID(FocusType.Passive);
        Event evt = Event.current;

        bool clicked = false;

        switch (evt.GetTypeForControl(id))
        {
            case EventType.MouseDown:
                if (evt.button == 0 && HandleUtility.nearestControl == id)
                {
                    GUIUtility.hotControl = id;

                    evt.Use(); // Using the MouseDown event
                    clicked = true;
                }
                break;

            case EventType.MouseMove:
                HandleUtility.Repaint(); 
                evt.Use(); // Using the MouseMove event
                break;

            case EventType.MouseUp:
                if (evt.button == 0 && HandleUtility.nearestControl == id)
                {
                    GUIUtility.hotControl = 0;
                    evt.Use(); // Using the MouseUp event
                }
                break;

            case EventType.Layout:
                HandleUtility.AddControl(id, HandleUtility.DistanceToCircle(worldpos, pickSize));
                // Keep in mind Layout events should not be Used!
                break;

            case EventType.Repaint:
                // Draw the handle here
                // Keep in mind Repaint events should not be Used!
                break;
        }

        return clicked;
    }
}