winform 用户控件事件的写法

 public partial class UcTest : UserControl
    {
        public UcTest()
        {
            InitializeComponent();
        }
        //定义事件
        public event EventHandler UserControlBtnClicked;
        private void btn_Click(object sender, EventArgs e)
        {
            UserControlBtnClicked?.Invoke(sender, new EventArgs());//把按钮自身作为参数传递
        }

    }