範例：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
namespace CancelAltAndF4
{
public partial class Frm_Main : Form
{
public Frm_Main()
{
InitializeComponent();
}
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.Alt && e.KeyValue == 115)//如果按下的Alt和F4
e.Handled = true;//不執行操作
}
}
}
