Win32 SetForegroundWindow unreliable

Question

I have a rather complex series of applications which depend on the ability to switch applications in the foreground.

My problem is, every 5 or 6 times of switching t

Answer 1

Try pushing the other application windows to the background first.

Also its a bit strange that you use SetWindowPos (SWP) to push a window to the foreground then push it out of the forgreound before using SetForegroundWindow to bring it back foward. Personally I've always used the SWP method without any issue ... but I've always pushed the other windows to the bottom as well.

Answer 2

Your AttachThreadInput() hack is (I think) a known way to defeat the focus stealing counter-measures in Windows. You are using the wrong handle though, you want to attach to the thread that currently has the focus. Which won't be hApp, you wouldn't need this code otherwise.

Use GetForegroundWindow() to get the handle to the window with the focus.

AttachThreadInput(
    GetWindowThreadProcessId(GetForegroundWindow(), NULL),
    GetCurrentThreadId(), TRUE
);

Although I think the 2nd argument needs to be thread ID of hApp. Because you don't want to shove your own window if I understood correctly. Not sure if that can work.

Answer 3

You also need to consider the chances of window being minimized. If the window or various application are minimized then SetForegroundWindow(hApp) won't work. To be safe use ShowWindow(hApp, 9); I prefer value 9. Have a look at its documentation and choose which you find fit for you.

Answer 4

I was having the same issue and I didn't want to mess up with threads. On experimenting I observed a simple hack to make SetForegroundWindow() work in the expected manner. Here is what I did:

1. Minimize the window if its not already minimized
2. Restore the minimized window
3. Call SetForegroundWindow(), and your window will be on top

Answer 5

The easiest solution in C# to bring a window in the foreground:

Once you have the handle for the window, you can simply call:

    SetWindowPos(handle, new IntPtr(0), 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_SHOWWINDOW);
    ShowWindow(handle, 5);
    SetForegroundWindow(handle);

    // If it is minimized, show the window
    if (IsIconic(handle))
    {
      ShowWindow(handle, 3);
    }

where

const int SWP_NOMOVE = 0x0002;
const int SWP_NOSIZE = 0x0001;
const int SWP_SHOWWINDOW = 0x0040;

Answer 6

Some windows are locked with setforeground(...), you need to unlock them. This sequence is useful with any window:

HWND needTopWindow=FindWindow(TEXT("classname"), TEXT("window name"));

the classname and window name you can retrieve with ranorexspy from e.g. nanoware.cz

if(!::IsWindow(needTopWindow)) return;

BYTE keyState[256] = {0};
//to unlock SetForegroundWindow we need to imitate Alt pressing
if(::GetKeyboardState((LPBYTE)&keyState))
    {
    if(!(keyState[VK_MENU] & 0x80))
        {
        ::keybd_event(VK_MENU, 0, KEYEVENTF_EXTENDEDKEY | 0, 0);
        }
    }

    ::SetForegroundWindow(needTopWindow);

if(::GetKeyboardState((LPBYTE)&keyState))
    {
        if(!(keyState[VK_MENU] & 0x80))
        {
            ::keybd_event(VK_MENU, 0, KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
        }
    }


        DWORD dwThreadID = GetWindowThreadProcessId(needTopWindow, NULL);
        AttachThreadInput( dwThreadID, GetCurrentThreadId(), true);

        SetWindowPos(needTopWindow, HWND_TOPMOST, NULL, NULL, NULL, NULL, SWP_NOMOVE | SWP_NOSIZE);
        SetWindowPos(needTopWindow, HWND_NOTOPMOST, NULL, NULL, NULL, NULL, SWP_NOMOVE | SWP_NOSIZE);

        SetForegroundWindow(needTopWindow);
        SetActiveWindow(needTopWindow);
        SetFocus(needTopWindow);

        AttachThreadInput( dwThreadID, GetCurrentThreadId(), false);