c# winform 如何获取F8 F9 按键 按下事件

keypress keydown 和重写ProcessCmdKey都试过了，现在所有按键都能捕捉了，唯独F8 F9 捕捉不了。求大佬解答

protected override bool ProcessCmdKey(ref Message msg, Keys keyCode)

我测试了，没有你说的情况

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Q759600
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.F8 || e.KeyCode == Keys.F9)
                MessageBox.Show("hello workd");
        }
    }
}