Bind with UXML and C# script

Version: 2021.3+

This example demonstrates how to create a binding and set the binding path with UXML, and call the Bind() method with a C# script.

Example overview

This example creates a custom Editor window with a TextField that binds to the name property of any GameObject in a scene.

You can find the completed files that this example creates in this GitHub repository.

先决条件

This guide is for developers familiar with the Unity Editor, UI Toolkit, and C# scripting. You are recommended to have a basic understanding of the following:

• Visual Tree
• UXML
• bindingPath
• Bind()

Define the binding path in UXML

Define the visual elements and the binding path in UXML.

1. Create a project in Unity with any template.

2. In your Project window, create a folder named bind-with-uxml-csharp folder to store all your files.

3. Create a UI Document named binding_example.uxml and replace its content with the following:

   <UXML xmlns:ui="UnityEngine.UIElements">
       <ui:VisualElement name="top-element">
           <ui:Label name="top-label" text="UXML-Defined Simple Binding"/>
           <ui:TextField name="GameObjectName" label="Name" text="" binding-path="m_Name"/>
       </ui:VisualElement>
   </UXML>
   

Create the binding in C#

Create the binding in a C# script and make an explicit call to the Bind() method.

1. Create a folder named Editor.

2. In the Editor folder, create a C# script file named SimpleBindingExampleUXML.cs.

3. Replace the contents of SimpleBindingExampleUXML.cs with the following:

   using UnityEditor;
   using UnityEngine;
   using UnityEditor.UIElements;
   using UnityEngine.UIElements;
   
   namespace UIToolkitExamples
   {
       public class SimpleBindingExampleUXML : EditorWindow
       {
           [SerializeField]
           VisualTreeAsset visualTree;
   
           [MenuItem("Window/UIToolkitExamples/Simple Binding Example UXML")]
           public static void ShowDefaultWindow()
           {
               var wnd = GetWindow<SimpleBindingExampleUXML>();
               wnd.titleContent = new GUIContent("Simple Binding UXML");
           }
   
           public void CreateGUI()
           {
               visualTree.CloneTree(rootVisualElement);
               OnSelectionChange();
           }
   
           public void OnSelectionChange()
           {
               GameObject selectedObject = Selection.activeObject as GameObject;
               if (selectedObject != null)
               {
                   // Create the SerializedObject from the current selection
                   SerializedObject so = new SerializedObject(selectedObject);
                   // Bind it to the root of the hierarchy. It will find the right object to bind to.
                   rootVisualElement.Bind(so);
               }
               else
               {
                   // Unbind the object from the actual visual element
                   rootVisualElement.Unbind();
   
                   // Clear the TextField after the binding is removed
                   var textField = rootVisualElement.Q<TextField>("GameObjectName");
                   if (textField != null)
                   {
                       textField.value = string.Empty;
                   }
               }
           }
       }
   }
   

4. In the Project window, select SimpleBindingExampleUXML.cs and drag binding_example.uxml to the Visual Tree field in the Inspector.

Test the binding

1. In Unity, select Window > UIToolkitExamples > Simple Binding Example UXML. A custom Editor window appears with a text field.
2. Select any GameObject in your scene. The name of the GameObject appears in your Editor window’s text field.
3. If you change the name of the GameObject in the text field, the name of the GameObject changes.

其他资源

• SerializedObject data binding
• Bindable elements
• Binding data type conversion
• Implementation details
• Binding examples