如何在c#.net winforms应用程序中编写alt+tab关闭按钮

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

public partial class MainForm : Form
{
    // 导入Windows API函数
    [DllImport("user32.dll")]
    private static extern bool RegisterHotKey(IntPtr hWnd, int id, int fsModifiers, int vk);

    [DllImport("user32.dll")]
    private static extern bool UnregisterHotKey(IntPtr hWnd, int id);

    // 定义常量
    private const int MOD_ALT = 0x0001;
    private const int VK_TAB = 0x09;
    private const int HOTKEY_ID = 1;

    public MainForm()
    {
        InitializeComponent();

        // 注册Alt+Tab热键
        RegisterHotKey(this.Handle, HOTKEY_ID, MOD_ALT, VK_TAB);
    }

    protected override void WndProc(ref Message m)
    {
        base.WndProc(ref m);

        // 捕捉热键消息
        if (m.Msg == 0x0312 && m.WParam.ToInt32() == HOTKEY_ID)
        {
            // 在这里编写关闭应用程序的代码
            this.Close();
        }
    }

    protected override void OnFormClosing(FormClosingEventArgs e)
    {
        // 注销热键
        UnregisterHotKey(this.Handle, HOTKEY_ID);

        base.OnFormClosing(e);
    }
}