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Resolved Is binding supposed to work?

Discussion in 'UI Toolkit' started by JasonC_, Jun 6, 2021.

  1. JasonC_

    JasonC_

    Joined:
    Oct 27, 2019
    Posts:
    66
    https://docs.unity3d.com/Packages/com.unity.ui@1.0/api/UnityEngine.UIElements.Toggle.html says:

    > To bind the Toggle's state to a boolean variable, set ... the C# bindingPath to the variable name.

    So I did that:

    Code (CSharp):
    1. using UnityEditor;
    2. using UnityEngine;
    3. using UnityEngine.UIElements;
    4.  
    5. public class SomeWindow : EditorWindow {
    6.  
    7.     [MenuItem("Window/Some Window")]
    8.     public static void ShowExample() => GetWindow<SomeWindow>();
    9.  
    10.     public bool SomeValue = true;
    11.  
    12.     public void CreateGUI () => rootVisualElement.Add(new Toggle("some value") {
    13.         bindingPath = "SomeValue"
    14.     });
    15.  
    16.     void Update () => Debug.Log(SomeValue);
    17.  
    18. }
    And it does nothing; just shows an (initially unchecked) box and prints "True" until the window is closed.

    What am I missing.... ? The binding system is fully implemented, right?

    2020.3.10f1
     
    Last edited: Jun 6, 2021
  2. Chris-Trueman

    Chris-Trueman

    Joined:
    Oct 10, 2014
    Posts:
    1,161
    The binding system is not fully implemented right now, it doesn't work at runtime or with anything other than a SerializedObject.
     
    JasonC_ likes this.
  3. JasonC_

    JasonC_

    Joined:
    Oct 27, 2019
    Posts:
    66
    Thanks. Disappointing, but at least I can stop scratching my head.

    So for now the only (non-IMGUI) option is to sync the value with the control manually? E.g.:

    Code (CSharp):
    1. using System.Diagnostics;
    2. using UnityEditor;
    3. using UnityEngine.UIElements;
    4. using Debug = UnityEngine.Debug;
    5.  
    6. public class SomeWindow : EditorWindow {
    7.  
    8.     [MenuItem("Window/Some Window")]
    9.     public static void ShowExample() => GetWindow<SomeWindow>();
    10.  
    11.     // ----- until binding api is complete: -----
    12.     // goal: toggle change reflected in property + property change reflected in toggle.
    13.  
    14.     bool someValue = true;
    15.     public bool SomeValue {
    16.         get => someValue;
    17.         set { toggle?.SetValueWithoutNotify(value); OnSomeValueChanged(someValue = value); }
    18.     }
    19.  
    20.     Toggle toggle;
    21.     void CreateGUI () {
    22.         rootVisualElement.Add(toggle = new Toggle("some value") { value = SomeValue });
    23.         toggle.RegisterValueChangedCallback((e) => SomeValue = e.newValue);
    24.     }
    25.  
    26.     // ----- end toggle setup, test code follows -----
    27.  
    28.     bool? prevValueForAssert;
    29.     void OnSomeValueChanged (bool newValue) {
    30.         Debug.Assert(SomeValue == newValue && someValue == newValue && newValue != prevValueForAssert);
    31.         prevValueForAssert = newValue;
    32.         Debug.Log($"some value: {someValue}");
    33.     }
    34.  
    35.     readonly Stopwatch timer = Stopwatch.StartNew();
    36.     void Update () {
    37.         for (; timer.ElapsedMilliseconds >= 2000; timer.Restart())
    38.             SomeValue = !SomeValue; // should not cause toggle cb feedback
    39.     }
    40.  
    41. }
    42.  
     
    Last edited: Jun 7, 2021
  4. martinpa_unity

    martinpa_unity

    Unity Technologies

    Joined:
    Oct 18, 2017
    Posts:
    189
    In your original snippet, what you are missing is an actual object to bind against. As @Chris-Trueman said, the current binding system only works with SerializedObject/SerializedProperty.

    To make your snippet work, you would need to add this line in the CreateGUI method:
    Code (CSharp):
    1. rootVisualElement.Bind(new SerializedObject(this));
     
    JasonC_ and Chris-Trueman like this.
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