Question

I’m using a C# app to listen for a global combination of keys (ctrl+F9) that will bring a specific window to front.

This is the code I’m using to bring a window to front, it works only if fired by a Button event:

    private void button3_Click(object sender, EventArgs e)
    {
        SetForegroundWindow(ptrActiveWindow.ToInt32());
        ShowWindowAsync(ptrActiveWindow, SW_RESTORE);
    }

For hooking, I’ve used a class taken from http://www.codeproject.com/KB/cs/CSLLKeyboardHook.aspx, which is fully listed here:

http://code.google.com/p/code-commenter/source/browse/trunk/key+preview/globalKeyboardHook.cs?spec=svn3&r=3

Whenever I have a F9 KeyUp event after a CTRL KeyDown and before a CTRL KeyUp (CTRL is still pressed), I call my method:

    private void restore(IntPtr hWnd)
    {

      IntPtr ptrCurrentActiveWindow = GetForegroundWindow(); //comment line
      ShowWindowAsync(ptrCurrentActiveWindow, SW_MINIMIZE); //comment line

        ShowWindowAsync(hWnd, SW_RESTORE);
        SetFocus(hWnd);
        SetForegroundWindow(hWnd.ToInt32());

    }

This does nothing. My window is activated in the background (I can see it blinking in the taskbar), but does not get restored.

The only way I can move around this is to use the commented code: minimize the currently active window and afterwards restore the window I want to see.

All help is appreciated,
Thanks.

Global hotkey, working version:

    private void Form1_Load(object sender, EventArgs e)
    {
        string atomName = Thread.CurrentThread.ManagedThreadId.ToString("X8") + this.GetType().FullName;
        short HotkeyID = GlobalAddAtom(atomName);
        if (!RegisterHotKey(this.Handle, HotkeyID, (uint)GlobalHotkeys.MOD_CONTROL, (uint)Keys.D5))
            listBox.Items.Add("failed: " + "unable to register hotkey. Error: " + Marshal.GetLastWin32Error().ToString());
        else
            listBox.Items.Add("succeeded adding hotkey id"+(uint)Keys.D5);
    }

    protected override void WndProc(ref Message m)
    {
        const int WM_HOTKEY = 0x0312;

        if (m.Msg == WM_HOTKEY)
        {
            if ((short)m.WParam==HotkeyID)
                listBox.Items.Add("Hotkey."+ (short)m.WParam);
        }
        base.WndProc(ref m);
    }

Answer 1

Your problem is that you didn’t register a global hotkey but used a keyboard hook instead. Keyboard hooks are not designed to be used as global hotkeys.

Use the RegisterHotKey function instead.
Check this example: http://www.pinvoke.net/default.aspx/user32.registerhotkey

Your immediate problem is that an application can’t put itself into the foreground whenever it likes. Because that’s annoying to the user. It can only do that during specific event. Like application startup or when handling a real global hotkey.

The system restricts which processes can set the foreground window. A process can set the foreground window only if one of the following conditions is true:

• The process is the foreground process.
• The process was started by the foreground process.
• The process received the last input event.
• There is no foreground process.
• The foreground process is being debugged.
• The foreground is not locked (see LockSetForegroundWindow).
• The foreground lock time-out has expired (see SPI_GETFOREGROUNDLOCKTIMEOUT in SystemParametersInfo).
• No menus are active.