public void OnPointerEnter(PointerEventData eventData)
{
graph.tooltip.Show();
object obj = node.GetInputValue <object>(port.fieldName, null);
if (obj == null)
{
obj = node.GetValue(port);
}
if (obj != null)
{
graph.tooltip.label.text = obj.ToString();
}
else
{
graph.tooltip.label.text = "n/a";
}
}