Instantiate UXML from C# scripts

To build UI from a UXML file:

1. Load the file into a VisualTreeAsset,.
2. Use either:
   • Instantiate() to instantiate without a parent, which creates a new TemplateContainer.
   • CloneTree(parent) to clone inside a parent.

Once the UXML is instantiated, you can retrieve specific elements from the visual tree with UQuery.

The following example creates a custom Editor window and loads a UXML file as its content:

using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;
using UnityEditor.UIElements;

public class MyWindow : EditorWindow  {
    [MenuItem ("Window/My Window")]
    public static void  ShowWindow () {
        EditorWindow w = EditorWindow.GetWindow(typeof(MyWindow));

        VisualTreeAsset uiAsset = AssetDatabase.LoadAssetAtPath<VisualTreeAsset>("Assets/MyWindow.uxml");
        VisualElement ui = uiAsset.Instantiate();

        w.rootVisualElement.Add(ui);
    }
}

To load UXML assets for runtime, set up VisualTreeAsset references in your MonoBehaviour scripts and assign the UXML assets from the Inspector. For more information and an example, refer to Support for runtime UI and Create a list view runtime UI.

Additional resources

• Load UXML and USS from C# scripts
• UQuery