Unity VisualElement CustomStyleProperties and Callbacks

UnityVisualElement.cs

class MyElement : VisualElement
{
    static readonly CustomStyleProperty<int> k_CellSizeProperty = new CustomStyleProperty<int>("--cell-size");
    static readonly CustomStyleProperty<Color> k_OddCellColorProperty = new CustomStyleProperty<Color>("--odd-cell-color");
    static readonly CustomStyleProperty<Color> k_EvenCellColorProperty = new CustomStyleProperty<Color>("--even-cell-color");
 
    int m_CellSize;
    Color m_OddCellColor;
    Color m_EvenCellColor;
 
    public MyElement()
    {
        RegisterCallback<CustomStyleResolvedEvent>(OnCustomStyleResolved);
    }
 
    void OnCustomStyleResolved(CustomStyleResolvedEvent e)
    {
        if (e.customStyle.TryGetValue(k_CellSizeProperty, out var cellSizeProperty))
            m_CellSize = cellSizeProperty;
 
        if (e.customStyle.TryGetValue(k_OddCellColorProperty, out var oddCellColor))
            m_OddCellColor = oddCellColor;
 
        if (e.customStyle.TryGetValue(k_EvenCellColorProperty, out var evenCellColor))
            m_EvenCellColor = evenCellColor;
    }
}