האזנה למקשים במהלך ריצת Windows

ניתן להוריד דוגמה פועלת מכאן

האזנה למקשים במהלך ריצה של Windows



יש להוסיף את המחלקה הבאה:

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);
  /// 

  /// Represents the window that is used internally to get the messages.
  /// 
  private class Window : NativeWindow, IDisposable
  {
    private static int WM_HOTKEY = 0x0312;

    public Window()
    {
    // create the handle for the window.
    this.CreateHandle(new CreateParams());
    }

    /// 

    /// Overridden to get the notifications.
    /// 
    /// 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 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);
        };
      }

      /// 

      /// Register the HotKey-s combination in the system as hot key.
      /// 
      /// The modifiers that are associated with the hot key (ModifierKeys. + Ctrl, Alt, Shift, Win)      /// The key itself that is associated with the hot key (A, B, C, etc.)      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.");
      }

      /// 

      /// A hot key has been pressed.
      /// 
      public event EventHandler KeyPressed;

      #region IDisposable Members

      public void Dispose()
      {
         // unregister all the registered hot keys.
         for (int i = _currentId; i > 0; i--)
         {
            UnregisterHotKey(_window.Handle, i);
         }

         // dispose the inner native window.
         _window.Dispose();
      }

      #endregion
    }

    /// 

    /// Event Args for the event that is fired after the hot key has been pressed.
    /// 
    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; }
      }
    }

    /// 

    /// The enumeration of possible modifiers.
    /// 
    [Flags]
    public enum ModifierKeys : uint
    {
        Alt = 1,
        Control = 2,
        Shift = 4,
        Win = 8
    }

לאחר מכן יש להשתמש בקוד הבא (בתוכנית עצמה):

public Form()
  {
    InitializeComponent();

    // register the event that is fired after the key press.
    hook.KeyPressed += new EventHandler(hook_KeyPressed);
    // register the control + alt + F12 combination as hot key.
    hook.RegisterHotKey(Key_Listener.ModifierKeys.Win | Key_Listener.ModifierKeys.Alt, Keys.D);
  }

  void hook_KeyPressed(object sender, KeyPressedEventArgs e)
  {
    // show the keys pressed in a label.
    label1.Text = e.Modifier.ToString() + " + " + e.Key.ToString();

    this.WindowState = FormWindowState.Normal;
  }