C#設置快捷鍵

要設置快捷鍵必須使用user32.dll下面的兩個方法。
BOOL RegisterHotKey( //註冊系統熱鍵的API函數
　HWND hWnd,
　int id,
　UINT fsModifiers,
　UINT vk
);
 
BOOL UnregisterHotKey( //刪除系統熱鍵的API函數
　HWND hWnd,
　int id
);
 
在C#中引用命名空間System.Runtime.InteropServices;來加載非託管類user32.dll
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
 
namespace HotKey
{
 
    public enum KeyModifiers //組合鍵枚舉
    {
        None = 0,
        Alt = 1,
        Control = 2,
        Shift = 4,
        Windows = 8
    }
 
    public partial class Form1 : Form
    {
        /*
         * RegisterHotKey函數原型及說明：
         * BOOL RegisterHotKey(
         * HWND hWnd,         // window to receive hot-key notification
         * int id,            // identifier of hot key
         * UINT fsModifiers, // key-modifier flags
         * UINT vk            // virtual-key code);
         * 參數 id爲你自己定義的一個ID值
         * 對一個線程來講其值必需在0x0000 - 0xBFFF範圍之內,十進制爲0~49151
         * 對DLL來講其值必需在0xC000 - 0xFFFF 範圍之內,十進制爲49152~65535
         * 在同一進程內該值必須唯一參數 fsModifiers指明與熱鍵聯合使用按鍵
         * 可取值爲：MOD_ALT MOD_CONTROL MOD_WIN MOD_SHIFT參數，或數字0爲無，1爲Alt,2爲Control，4爲Shift，8爲Windows
         * vk指明熱鍵的虛擬鍵碼
         */
 
        [System.Runtime.InteropServices.DllImport("user32.dll")] //申明API函數
        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函數
        public static extern bool UnregisterHotKey(
         IntPtr hWnd, // handle to window
         int id // hot key identifier
        );
        public Form1()
        {
            InitializeComponent();
        }
        private void ProcessHotkey(Message m) //按下設定的鍵時調用該函數
        {
            IntPtr id = m.WParam; //IntPtr用於表示指針或句柄的平臺特定類型
            //MessageBox.Show(id.ToString());
            string sid = id.ToString();
            switch (sid)
            {
                case "100":
                    MessageBox.Show("調用A函數");
                    break;
                case "200":
                    MessageBox.Show("調用B函數");
                    break;
            }
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            //Handle爲當前窗口的句柄,繼續自Control.Handle,Control爲定義控件的基類
            //RegisterHotKey(Handle, 100, 0, Keys.A); //註冊快捷鍵,熱鍵爲A
            //RegisterHotKey(Handle, 100, KeyModifiers.Alt | KeyModifiers.Control, Keys.B);//這時熱鍵爲Alt+CTRL+B
            //RegisterHotKey(Handle, 100, 1, Keys.B); //1爲Alt鍵，熱鍵爲Alt+B
            RegisterHotKey(Handle, 100, 2,Keys.A); //定義熱鍵爲Alt+Tab，這裏實現了屏幕系統Alt+Tab鍵
            RegisterHotKey(Handle, 200, 2, Keys.B); //註冊2個熱鍵,根據id值100,200來判斷需要執行哪個函數
        }
 
        private void button1_Click(object sender, EventArgs e) //重新設置熱鍵
        {
            UnregisterHotKey(Handle, 100);//卸載快捷鍵
            RegisterHotKey(Handle, 100, 2, Keys.C); //註冊新的快捷鍵，參數0表示無組合鍵
        }
 
        private void Form1_FormClosing(object sender, FormClosingEventArgs e) //退出程序時缷載熱鍵
        {
            UnregisterHotKey(Handle, 100);//卸載第1個快捷鍵
            UnregisterHotKey(Handle, 200); //缷載第2個快捷鍵
        }
 
        //重寫WndProc()方法，通過監視系統消息，來調用過程
        protected override void WndProc(ref Message m)//監視Windows消息
        {
            const int WM_HOTKEY = 0x0312;//如果m.Msg的值爲0x0312那麼表示用戶按下了熱鍵
            switch (m.Msg)
            {
                case WM_HOTKEY:
                    ProcessHotkey(m);//按下熱鍵時調用ProcessHotkey()函數
                    break;
            }
            base.WndProc(ref m); //將系統消息傳遞自父類的WndProc
        }
    }