FN-Lock preparations

app/KeyboardHook.cs

@@ -0,0 +1,164 @@
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+
+public sealed class KeyboardHook : IDisposable
+{
+    // Registers a hot key with Windows.
+    [DllImport("user32.dll")]
+    private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);
+    // Unregisters the hot key with Windows.
+    [DllImport("user32.dll")]
+    private static extern bool UnregisterHotKey(IntPtr hWnd, int id);
+
+    [DllImport("user32.dll")]
+    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);
+
+    [DllImport("user32.dll", SetLastError = true)]
+    public static extern void keybd_event(byte virtualKey, byte scanCode, uint flags, IntPtr extraInfo);
+
+    public const int KEYEVENTF_EXTENDEDKEY = 1;
+    public const int KEYEVENTF_KEYUP = 2;
+
+    public static void KeyPress(Keys key)
+    {
+        keybd_event((byte)key, 0, KEYEVENTF_EXTENDEDKEY, IntPtr.Zero);
+    }
+
+    /// <summary>
+    /// Represents the window that is used internally to get the messages.
+    /// </summary>
+    private class Window : NativeWindow, IDisposable
+    {
+        private static int WM_HOTKEY = 0x0312;
+        public static Keys? fakeKey;
+
+        public Window()
+        {
+            // create the handle for the window.
+            this.CreateHandle(new CreateParams());
+        }
+
+        /// <summary>
+        /// Overridden to get the notifications.
+        /// </summary>
+        /// <param name="m"></param>
+        protected override void WndProc(ref Message m)
+        {
+            base.WndProc(ref m);
+
+            // check if we got a hot key pressed.
+            if (m.Msg == WM_HOTKEY)
+            {
+                // get the keys.
+                Keys key = (Keys)(((int)m.LParam >> 16) & 0xFFFF);
+                ModifierKeys modifier = (ModifierKeys)((int)m.LParam & 0xFFFF);
+
+                // invoke the event to notify the parent.
+                if (KeyPressed != null)
+                    KeyPressed(this, new KeyPressedEventArgs(modifier, key));
+            }
+        }
+
+        public event EventHandler<KeyPressedEventArgs> KeyPressed;
+
+        #region IDisposable Members
+
+        public void Dispose()
+        {
+            this.DestroyHandle();
+        }
+
+        #endregion
+    }
+
+    private Window _window = new Window();
+    private int _currentId;
+
+    public KeyboardHook()
+    {
+        // register the event of the inner native window.
+        _window.KeyPressed += delegate (object sender, KeyPressedEventArgs args)
+        {
+            if (KeyPressed != null)
+                KeyPressed(this, args);
+        };
+    }
+
+    /// <summary>
+    /// Registers a hot key in the system.
+    /// </summary>
+    /// <param name="modifier">The modifiers that are associated with the hot key.</param>
+    /// <param name="key">The key itself that is associated with the hot key.</param>
+    public void RegisterHotKey(ModifierKeys modifier, Keys key)
+    {
+        // increment the counter.
+        _currentId = _currentId + 1;
+
+        // register the hot key.
+        if (!RegisterHotKey(_window.Handle, _currentId, (uint)modifier, (uint)key))
+            throw new InvalidOperationException("Couldn’t register the hot key.");
+    }
+
+    /// <summary>
+    /// A hot key has been pressed.
+    /// </summary>
+    public event EventHandler<KeyPressedEventArgs> KeyPressed;
+
+    #region IDisposable Members
+
+    public void UnregisterAll()
+    {
+        // unregister all the registered hot keys.
+        for (int i = _currentId; i > 0; i--)
+        {
+            UnregisterHotKey(_window.Handle, i);
+        }
+    }
+
+    public void Dispose()
+    {
+        UnregisterAll();
+        // dispose the inner native window.
+        _window.Dispose();
+    }
+
+    #endregion
+}
+
+/// <summary>
+/// Event Args for the event that is fired after the hot key has been pressed.
+/// </summary>
+public class KeyPressedEventArgs : EventArgs
+{
+    private ModifierKeys _modifier;
+    private Keys _key;
+
+    internal KeyPressedEventArgs(ModifierKeys modifier, Keys key)
+    {
+        _modifier = modifier;
+        _key = key;
+    }
+
+    public ModifierKeys Modifier
+    {
+        get { return _modifier; }
+    }
+
+    public Keys Key
+    {
+        get { return _key; }
+    }
+}
+
+/// <summary>
+/// The enumeration of possible modifiers.
+/// </summary>
+[Flags]
+public enum ModifierKeys : uint
+{
+    None = 0,
+    Alt = 1,
+    Control = 2,
+    Shift = 4,
+    Win = 8
+}