在WPF中使用全局快捷键

今天写一个小程序中使用到了全局快捷键，找到了我之前写的文章在c#中使用全局快捷键翻了一下，发现它是WinForm版本的，而我现在大部分写WPF程序了，便将其翻译了为WPF版本的了。

     static class Hotkey
     {
         #region 系统api
         [DllImport("user32.dll")]
         [return: MarshalAs(UnmanagedType.Bool)]
         static extern bool RegisterHotKey(IntPtr hWnd, int id, HotkeyModifiers fsModifiers, uint vk);

         [DllImport("user32.dll")]
         static extern bool UnregisterHotKey(IntPtr hWnd, int id);
         #endregion

         /// <summary>
         /// 注册快捷键
         /// </summary>
         /// <param name="window">持有快捷键窗口</param>
         /// <param name="fsModifiers">组合键</param>
         /// <param name="key">快捷键</param>
         /// <param name="callBack">回调函数</param>
         public static void Regist(Window window, HotkeyModifiers fsModifiers, Key key, HotKeyCallBackHanlder callBack)
         {
             var hwnd = new WindowInteropHelper(window).Handle;
             var _hwndSource = HwndSource.FromHwnd(hwnd);
             _hwndSource.AddHook(WndProc);

             int id = keyid++;

             var vk = KeyInterop.VirtualKeyFromKey(key);
             if (!RegisterHotKey(hwnd, id, fsModifiers, (uint)vk))
                 throw new Exception("regist hotkey fail.");
             keymap[id] = callBack;
         }

         /// <summary>
         /// 快捷键消息处理
         /// </summary>
         static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
         {
             if (msg == WM_HOTKEY)
             {
                 int id = wParam.ToInt32();
                 if (keymap.TryGetValue(id, out var callback))
                 {
                     callback();
                 }
             }
             return IntPtr.Zero;
         }

         /// <summary>
         /// 注销快捷键
         /// </summary>
         /// <param name="hWnd">持有快捷键窗口的句柄</param>
         /// <param name="callBack">回调函数</param>
         public static void UnRegist(IntPtr hWnd, HotKeyCallBackHanlder callBack)
         {
             foreach (KeyValuePair<int, HotKeyCallBackHanlder> var in keymap)
             {
                 if (var.Value == callBack)
                     UnregisterHotKey(hWnd, var.Key);
             }
         }

         const int WM_HOTKEY = 0x312;
         static int keyid = ;
         static Dictionary<int, HotKeyCallBackHanlder> keymap = new Dictionary<int, HotKeyCallBackHanlder>();

         public delegate void HotKeyCallBackHanlder();
     }

     enum HotkeyModifiers
     {
         MOD_ALT = 0x1,
         MOD_CONTROL = 0x2,
         MOD_SHIFT = 0x4,
         MOD_WIN = 0x8
     }

代码仍然差不多，使用的方式更加简单一点：

protected override void OnSourceInitialized(EventArgs e)
{
    Hotkey.Regist(this, HotkeyModifiers.MOD_ALT, Key.T, () =>
    {
        MessageBox.Show("hello");
    });

_context = new MainContext();
    this.DataContext = _context;
    _context.Process();
}

需要注意的是，调用Hotkey.Regist函数时，需要窗口是分配了句柄的，因此建议在OnLoad事件或OnSourceInitialized函数中进行。