FindWindow GetLastError 5 ERROR_ACCESS_DENIED

Question

我在底层键盘挂钩过程中调用WIN32 API FindWindow（），试图将焦点设置到我的Python脚本GUI窗口（这是tkinter顶层窗口之一），但是每次获取结果为NULL时，并且GetLastError（）始终返回5（ERROR_ACCESS_DENIED），有人知道原因吗？它运行在WIN10 64位系统上。

LRESULT CALLBACK MyllKeyboardProc(
    _In_ int    nCode,  
    _In_ WPARAM wParam,
    _In_ LPARAM lParam)
{
    if (nCode < 0)
    {
        return CallNextHookEx(hHookllkb, nCode, wParam, lParam);
    }
    else
    {
        //printf("Key paras:%d %d %d\n", nCode, wParam, lParam);
        KBDLLHOOKSTRUCT *Key_Info = (KBDLLHOOKSTRUCT*)lParam;
        if (HC_ACTION == nCode)
        {
            if (WM_KEYDOWN == wParam)  //如果按键为按下状态
            {
                /*
                if (Key_Info->vkCode == VK_LWIN || Key_Info->vkCode == VK_RWIN) //屏敝 WIN(左右) 键
                {
                    return TRUE;
                }
                if (Key_Info->vkCode == 0x4D && ((GetKeyState(VK_LWIN) & 0x8000) ||
                    (GetKeyState(VK_RWIN) & 0x8000))) //屏敝 WIN+D 组合键(左右)
                {
                    return TRUE;
                }
                if (Key_Info->vkCode == 0x44 && ((GetKeyState(VK_LWIN) & 0x8000) ||
                    (GetKeyState(VK_LWIN) & 0x8000)))  //屏敝 WIN+M 组合键(左右)
                {
                    return TRUE;
                }
                */
                if (Key_Info->vkCode == VK_F11 && GetKeyState(VK_CONTROL) & 0x8000) //屏敝 CTRL + F12 组合键
                {

                    //printf("CTRL+F2 %x\n", wParam);
                    if (bHide)
                        bHide = FALSE;
                    else
                        bHide = TRUE;
                    HideTaskBar(bHide);
                    return TRUE;
                }
                if (Key_Info->vkCode == VK_F12 && GetKeyState(VK_CONTROL) & 0x8000) //屏敝 CTRL + F11 组合键
                {
                    int nCmdShow;
                    if (bHideConsole)
                    {
                        nCmdShow = SW_SHOW;
                        bHideConsole = FALSE;
                    }
                    else
                    {
                        nCmdShow = SW_HIDE;
                        bHideConsole = TRUE;
                    }
                    ShowWindow(hWndConsole, nCmdShow);
                    if (hWndConsole && !bHideConsole)
                    {
                        //Tricks for stealing keyboard input focus. it works
                        ShowWindow(hWndConsole, SW_HIDE);
                        ShowWindow(hWndConsole, SW_SHOW);
                        HWND hWndFocus = NULL;
                        if(bScriptRunning==TRUE){
                            HWND hWndRun = FindWindow(NULL, _T("The user interface for A - code supervision"));
                            if (hWndRun)
                            {
                                printf("Py running GUI window found:%x\n", hWndRun);
                                hWndFocus = hWndRun;
                                SetForegroundWindow(hWndFocus);
                                SetFocus(hWndFocus);
                                SetActiveWindow(hWndFocus);
                                EnableWindow(hWndFocus, TRUE);
                            }
                            else
                            {
                                printf("Py running GUI window not found error code: %d\n", GetLastError());
                            }
                        }
                        else {
                            hWndFocus = hWndConsole;
                            SetForegroundWindow(hWndFocus);
                            SetFocus(hWndFocus);
                            SetActiveWindow(hWndFocus);
                            EnableWindow(hWndFocus, TRUE);
                        }
                    }
                    return TRUE;
                }
                /*
                if (Key_Info->vkCode == VK_TAB && Key_Info->flags & LLKHF_ALTDOWN) //屏敝 ATL + TAB 组合键
                {
                    return TRUE;
                }
                if (Key_Info->vkCode == VK_ESCAPE && Key_Info->flags & LLKHF_ALTDOWN) //屏敝 ATL + ESC 组合键
                {
                    return TRUE;
                }
                */
            }

        }
        return CallNextHookEx(hHookllkb, nCode, wParam, lParam);
    }
}