using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.InteropServices;

using System.Text;

using System.Threading.Tasks;

using System.Windows;

using System.Windows.Forms;

using System.Windows.Interop;

namespace WpfHotKey

{

    public class HotKeyHelper

    {

        /// <summary>

        /// 如果函数执行成功，返回值不为0。

        /// 如果函数执行失败，返回值为0。要得到扩展错误信息，调用GetLastError。.NET方法:Marshal.GetLastWin32Error()

        /// </summary>

        /// <param name="hWnd">要定义热键的窗口的句柄</param>

        /// <param name="id">定义热键ID（不能与其它ID重复）  </param>

        /// <param name="fsModifiers">标识热键是否在按Alt、Ctrl、Shift、Windows等键时才会生效</param>

        /// <param name="vk">定义热键的内容,WinForm中可以使用Keys枚举转换，

        /// WPF中Key枚举是不正确的,应该使用System.Windows.Forms.Keys枚举，或者自定义正确的枚举或int常量</param>

        /// <returns></returns>

        [DllImport("user32.dll", SetLastError = true)]

        static extern bool RegisterHotKey(

            IntPtr hWnd,

            int id,

            KeyModifiers fsModifiers,

            int vk

            );

        /// <summary>

        /// 取消注册热键

        /// </summary>

        /// <param name="hWnd">要取消热键的窗口的句柄</param>

        /// <param name="id">要取消热键的ID</param>

        /// <returns></returns>

        [DllImport("user32.dll", SetLastError = true)]

        static extern bool UnregisterHotKey(

            IntPtr hWnd,

            int id

            );

        /// <summary>

        /// 向全局原子表添加一个字符串，并返回这个字符串的唯一标识符,成功则返回值为新创建的原子ID,失败返回0

        /// </summary>

        /// <param name="lpString"></param>

        /// <returns></returns>

        [DllImport("kernel32", SetLastError = true)]

        static extern short GlobalAddAtom(string lpString);

        [DllImport("kernel32", SetLastError = true)]

        static extern short GlobalDeleteAtom(short nAtom);

        /// <summary>

        /// 定义了辅助键的名称（将数字转变为字符以便于记忆，也可去除此枚举而直接使用数值）

        /// </summary>

        [Flags()]

        public enum KeyModifiers

        {

            None = ,

            Alt = ,

            Ctrl = ,

            Shift = ,

            WindowsKey =

        }

        /// <summary>

        /// 热键的对应的消息ID

        /// </summary>

        public const int WM_HOTKEY = 0x312;

        static Dictionary<int, Action> keymap = new Dictionary<int, Action>();   //每一个key对于一个处理函数

        /// <summary>

        /// 注册快捷键

        /// </summary>

        /// <param name="window">主体窗体</param>

        /// <param name="action">回调的方法</param>

        /// <returns>热键的标识</returns>

        public static void Regist(Window window, Action action)

        {

            HwndSource hWndSource;

            WindowInteropHelper wih = new WindowInteropHelper(window);

            hWndSource = HwndSource.FromHwnd(wih.Handle);

            //添加处理程序

            hWndSource.AddHook(MainWindowProc);

            int KeyCodes = -;

            if (!RegisterHotKey(wih.Handle, KeyCodes, HotKeyHelper.KeyModifiers.Ctrl, (int)Keys.S))

            {

                throw new Exception("注册失败");

            }

            else

            {

                if (keymap.Where(p => p.Key == KeyCodes).Count() > )

                    throw new Exception("注册失败,应为这个组合键已经注册！！");

                else

                {

                    keymap.Add(KeyCodes, action);

                }

            }

        }

        /// <summary>

        /// 卸载快捷键

        /// </summary>

        /// <param name="window">主体窗体</param>

        /// <param name="callBack">注册时回调的方法</param>

        public static void UnRegist(Window window, Action callBack)

        {

            foreach (KeyValuePair<int, Action> var in keymap)

            {

                WindowInteropHelper wih = new WindowInteropHelper(window);

                if (var.Value == callBack)

                {

                    UnregisterHotKey(wih.Handle, var.Key);

                    keymap.Remove(var.Key);

                    return;

                }

            }

        }

        private static IntPtr MainWindowProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)

        {

            switch (msg)

            {

                case HotKeyHelper.WM_HOTKEY:

                    {

                        int sid = wParam.ToInt32();

                        if (keymap.Where(p => p.Key == sid).Count() > )

                        {

                            keymap.Where(p => p.Key == sid).FirstOrDefault().Value.Invoke();

                        }

                        handled = true;

                        break;

                    }

            }

            return IntPtr.Zero;

        }

    }

}