c# 禁用Excel窗口关闭按钮

using System;

using System.Runtime.InteropServices;

class Win32
{
    /// <summary>
    /// 查找窗口句柄
    /// </summary>
    /// <param name="lpClassName">窗口类名</param>
    /// <param name="lpWindowName">窗口标题</param>
    /// <returns></returns>
    [DllImport("user32")]
    public static extern int FindWindow(string lpClassName, string lpWindowName);

    [DllImport("user32")]
    public static extern int GetSystemMenu(int hwnd, int bRevert);

    [DllImport("user32")]
    public static extern int RemoveMenu(int hMenu, int nPosition, int wFlags);

}

private void button1_Click(object sender, EventArgs e)
        {
            if (button1.Text == "禁用关闭")
            {
                DisableClose();
                MessageBox.Show("Excel关闭已禁用");
                button1.Text = "已禁用";
            }
        }

        public const int MF_BYPOSITION = 0x400;

        protected void DisableClose()
        {
            int excel = Win32.FindWindow("XLMAIN", null);//Excel2003窗体类

            int close = Win32.GetSystemMenu(excel,0);

            Win32.RemoveMenu(close, 6, MF_BYPOSITION);
        }