WinAPI在DLL中创建窗口

Question

I injected a dll into the game process, and then dll create hook which creates, a new thread to handle the windows event.

Thread function:

void CFile::winThread(void *pData)
{
    CFile *pThis = reinterpret_cast<CFile*>(pData);

    // Common controls init
    INITCOMMONCONTROLSEX iCC;
    iCC.dwSize = sizeof(INITCOMMONCONTROLSEX);
    iCC.dwICC = ICC_BAR_CLASSES;

    InitCommonControlsEx(&iCC);

    pThis->m_pConnect = new WinConnect(300, 180);
    pThis->m_pConnect->setText("Connecting");
    pThis->m_pConnect->show();

    MSG message;
    while (GetMessage(&message, 0, 0, 0))
    {
        TranslateMessage(&message);
        DispatchMessage(&message);
    }

    tthread::mutex _mutex;
    _mutex.lock();
    pThis->m_bIsFinished = true;
    _mutex.unlock();
}

WinConnect.cpp

WinConnect::WinConnect(int width, int height)
{
    if (registerWin())
    {
        int screenWidth = GetSystemMetrics(SM_CXSCREEN);
        int screenHeight = GetSystemMetrics(SM_CYSCREEN);
        int x = (screenWidth / 2) - (width / 2);
        int y = (screenHeight / 2) - (height / 2);

        m_hWin = CreateWindowExA(WS_EX_CLIENTEDGE, winNameConnect, "Test Window",
            WS_POPUP | WS_BORDER | WS_CAPTION,
            x, y + 200, width, height, NULL, NULL, GetModuleHandle(NULL), NULL);

        printf("GetLastError %d\n", GetLastError());

        if (m_hWin)
        {
            RECT size;
            GetClientRect(m_hWin, &size);

            int winH = size.bottom - size.top;
            int winW = size.right - size.left;
            int buttonW = winW / 2;

            m_hLInfo = CreateWindowEx(0, "STATIC", "",
            WS_VISIBLE | WS_CHILD | SS_CENTER | SS_CENTERIMAGE,
            7, 7, winW - 14, winH - 41, m_hWin, NULL, GetModuleHandle(NULL), NULL);

            printf("GetLastError %d\n", GetLastError());

            // 9 pix odstep height
            m_hBCancel = CreateWindowEx(0, "BUTTON", "Cancel",
                WS_VISIBLE | WS_CHILD | SS_CENTER,
                buttonW / 2, winH - 30, buttonW, 25, m_hWin, NULL, GetModuleHandle(NULL), NULL);

            printf("GetLastError %d\n", GetLastError());
        }       
    }
}

bool WinConnect::registerWin()
{
    WNDCLASSEX winClass;

    winClass.hInstance = GetModuleHandle(NULL);
    winClass.lpszClassName = winNameConnect;
    winClass.lpfnWndProc = wndProc;
    winClass.style = CS_DBLCLKS;
    winClass.cbSize = sizeof(WNDCLASSEX);
    winClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    winClass.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    winClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    winClass.lpszMenuName = NULL;
    winClass.cbClsExtra = 0;
    winClass.cbWndExtra = 0;
    winClass.hbrBackground = (HBRUSH)COLOR_BACKGROUND;

    if (!RegisterClassEx(&winClass))
        return false;

    return true;
}

The output of GetLastError is:

GetLastError 0

GetLastError 127

GetLastError 127

I can't figure out why this label and button are not created. Window always is created, witchout any problem. Any help?

Answer 1

Firstly, as stated in the comments, GetLastError 's result is meaningless unless the previous function actually failed. So you would have to check for instance whether m_hLInfo == NULL first (which I guess it is, though).

About the actual problem: It looks to me like your code is using the Unicode-version of the Windows API but feeding it ANSI strings.

The reason why the window is created correctly is that you explicitely call CreateWindowExA (notice the A ) which is the ANSI-version of the function. For the button and the label you call CreateWindowEx which your header files have #define 'd as CreateWindowExW , the Unicode-version. But your class names ( "STATIC" and "BUTTON" ) are not Unicode, though! (So Windows tries to create windows with mojibake classnames, which will of course fail horribly.)

So you could either change CreateWindowEx to CreateWindowExA everywhere, or - better - use proper Unicode strings everywhere: Remove the A from CreateWindowExA and prepend all strings you feed WinAPI function with L , eg L"BUTTON" . (Or, if you are not sure that you will always be in a Unicode compiler environment, you can use the _T macro, eg _T("BUTTON") .)

Further reading:
Wikibooks article
MSDN article