Why does WPF use this way of specifying event handling?

Question

WPF

Standard solution. It is also used in android and java:

class Element
{
    public event EventHandler Click;
    protected void OnClick(EventArgs e)
    {
        Click?.Invoke(this, e);
    }
}

But why is this added to wpf for the UI event handler:

private void Window_Deactivated(object sender, EventArgs e)
        {
            ....
        }

Question: Why exactly, and not as in the first option?

Answer 1

Read about delegates and understand what Click?.Invoke(this, e);