如果 Changed 是 EventCallback 类型，为什么我们不能使用？ 在 Changed?.InvokeAsync()?

Question

I wonder why I cannot use ?. (null conditional operator) in the following.

[Parameter] public EventCallback Changed {get; set;}
private void OnChanged()
{
  Changed?.InvokeAsync();
}

Answer 1

EventCallback is a struct which are, by design, non-nullable .