C# 設定全域熱鍵

Code
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;
using System.Collections;

namespace HotKey1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public delegate void HotkeyEventHandler(int HotKeyID);
        private int Hotkey1;
        public class Hotkey : System.Windows.Forms.IMessageFilter
        {
            Hashtable keyIDs = new Hashtable();
            IntPtr hWnd;

            public event HotkeyEventHandler OnHotkey;

            public enum KeyFlags
            {
                MOD_ALT = 0x1,
                MOD_CONTROL = 0x2,
                MOD_SHIFT = 0x4,
                MOD_WIN = 0x8
            }
            [DllImport("user32.dll")]
            public static extern UInt32 RegisterHotKey(IntPtr hWnd, UInt32 id, UInt32 fsModifiers, UInt32 vk);

            [DllImport("user32.dll")]
            public static extern UInt32 UnregisterHotKey(IntPtr hWnd, UInt32 id);

            [DllImport("kernel32.dll")]
            public static extern UInt32 GlobalAddAtom(String lpString);

            [DllImport("kernel32.dll")]
            public static extern UInt32 GlobalDeleteAtom(UInt32 nAtom);

            public Hotkey(IntPtr hWnd)
            {
                this.hWnd = hWnd;
                Application.AddMessageFilter(this);
            }

            public int RegisterHotkey(Keys Key, KeyFlags keyflags)
            {
                UInt32 hotkeyid = GlobalAddAtom(System.Guid.NewGuid().ToString());
                RegisterHotKey((IntPtr)hWnd, hotkeyid, (UInt32)keyflags, (UInt32)Key);
                keyIDs.Add(hotkeyid, hotkeyid);
                return (int)hotkeyid;
            }

            public void UnregisterHotkeys()
            {
                Application.RemoveMessageFilter(this);
                foreach (UInt32 key in keyIDs.Values)
                {
                    UnregisterHotKey(hWnd, key);
                    GlobalDeleteAtom(key);
                }
            }

            public bool PreFilterMessage(ref System.Windows.Forms.Message m)
            {
                if (m.Msg == 0x312)
                {
                    if (OnHotkey != null)
                    {
                        foreach (UInt32 key in keyIDs.Values)
                        {
                            if ((UInt32)m.WParam == key)
                            {
                                OnHotkey((int)m.WParam);
                                return true;
                            }
                        }
                    }
                }
                return false;
            }
        }

        public void OnHotkey(int HotkeyID) //Ctrl+F2隱藏表單，再按顯示表單。
        {
            if (HotkeyID == Hotkey1)
            {
                if (this.Visible == true)
                    this.Visible = false;
                else
                    this.Visible = true;
            }
            else
            {
                this.Visible = false;
            }
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Hotkey hotkey;
            hotkey = new Hotkey(this.Handle);
            Hotkey1 = hotkey.RegisterHotkey(System.Windows.Forms.Keys.F2, Hotkey.KeyFlags.MOD_CONTROL);   //定義快鍵(Ctrl + F2)
            hotkey.OnHotkey += new HotkeyEventHandler(OnHotkey);
        }
    }
}