private void OnEnable()
    {
        GenerateToolbar();

        _graphView = new GraphViewExample()
        {
            style = { flexGrow = 1 }
        };
        rootVisualElement.Add(_graphView);


        rootVisualElement.Add(new Button(_graphView.Exe)
        {
            text = "実行"
        });
    }
 public void Initialize(GraphViewExample graphView)
 {
     this.graphView = graphView;
 }