注册系统热键

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


namespace HotKeyApp
...{
    public partial class Form1 : Form
    ...{
        [System.Runtime.InteropServices.DllImport("user32.dll")] //申明API函数 
        public static extern bool RegisterHotKey(
        IntPtr hWnd, // handle to window 
        int id, // hot key identifier 
        uint fsModifiers, // key-modifier options 
        Keys vk // virtual-key code 
        );

        [System.Runtime.InteropServices.DllImport("user32.dll")] //申明API函数 
        public static extern bool UnregisterHotKey(
        IntPtr hWnd, // handle to window 
        int id // hot key identifier 
        );

        public enum KeyModifiers
        ...{
            None = 0,
            Alt = 1,
            Control = 2,
            Shift = 4,
            Windows = 8
        }

        public Form1()
        ...{
            InitializeComponent();

            RegisterHotKey(Handle, 100, 2, Keys.U); 
        }
        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        ...{
            UnregisterHotKey(Handle, 100); //卸载第1个快捷键 
        }


        protected override void WndProc(ref Message m)//监视Windows消息 
        ...{
            const int WM_HOTKEY = 0x0312; //如果m.Msg的值为0x0312那么表示用户按下了热键 
            switch (m.Msg)
            ...{
                case WM_HOTKEY:
                    ProcessHotkey(m); //按下热键时调用ProcessHotkey()函数
                    break;
            }

            base.WndProc(ref m); //将系统消息传递自父类的WndProc 

        }

        private void ProcessHotkey(Message m)
        ...{
            IntPtr id = m.WParam; //IntPtr用于表示指针或句柄的平台特定类型 
            //MessageBox.Show(id.ToString()); 
            string sid = id.ToString();
            switch (sid)
            ...{
                case "100": this.Show(); break; // 
            }
        }

        private void button1_Click(object sender, EventArgs e)
        ...{
            this.Hide();
        }
    }
}