Win32 MessageBox没有出现

Question

我遇到了一个奇怪的问题.我正在VC++ 2008中创建一个Win32应用程序,使得一个类可以封装大部分工作,以便在调用时轻松重复MessageBox.消息框`已创建(我认为),但除非我按下Alt键,否则不会显示!

究竟发生了什么:

1. 我运行程序

2. 按Enter键

3. 主窗口失去焦点

4. 当我点击主窗口时发出哔声,好像有一个模态MessageBox

5. 要么按Escape ...要么获得焦点要么按Alt键,然后按下Alt键出现MessageBox(即菜单会掉落)!!!!!!

PS它工作正常,但突然发生了这种情况.我没有发现任何差异 - 我甚至做了一个新项目!

这应该是主程序:

int APIENTRY _tWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR    lpCmdLine, int       nCmdShow)
{
    MSG msg;
    CWnd    cMainWindow(TEXT("DentoMan"), TEXT("Bejkoman")); // pass The class name and window name to the constructor

    cMainWindow.CreateDef(); //Create the Window
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}

虽然这是类文件

CWnd::CWnd() {
};

CWnd::CWnd(LPTSTR lpszClassName, LPTSTR lpszWindowName) {
    CWnd::lpszClassName     = lpszClassName;
    CWnd::lpszWindowName    = lpszWindowName;
};

CWnd::~CWnd() {
};

// Create the window with default parameters
HWND CWnd::CreateDef(void) {
    WNDCLASSEX wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = StaticWndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = (HINSTANCE)GetModuleHandle(NULL);
    wcex.hIcon          = 0;
    wcex.hCursor        = LoadCursor(NULL, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW + 4);
    wcex.lpszMenuName   = 0;
    wcex.lpszClassName  = lpszClassName;
    wcex.hIconSm        = 0;

    RegisterClassEx(&wcex);
    g_hWnd = CreateWindowEx(0,lpszClassName, lpszWindowName, WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, wcex.hInstance, this);
    hInst   =   wcex.hInstance;  //Store hInstance in the class hInst variable

    if (!g_hWnd) return false;
    ShowWindow(g_hWnd, SW_SHOW);
    UpdateWindow(g_hWnd);

    return g_hWnd;
}

LRESULT CALLBACK CWnd::StaticWndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    /* The Only Message we take here so we store the 'this' pointer within the window to identify messages 
    comming from it by the 'this' pointer*/
    if ( Message == WM_CREATE ) {
        SetWindowLong( hWnd, GWL_USERDATA, (LONG)((CREATESTRUCT FAR *)lParam)->lpCreateParams);
    }

    /* Store the window pointer in the class pointer we just created in order to run the right public WndPRoc */
    CWnd *Destination = (CWnd*)GetWindowLong( hWnd, GWL_USERDATA );

    // If the hWnd has a related class, pass it through
    if (Destination) {
        return Destination->WndProc( hWnd, Message, wParam, lParam );
    }

    // No destination found, defer to system...
    return DefWindowProc( hWnd, Message, wParam, lParam );
};

LRESULT CWnd::WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam) {
    // Determine message type
    switch (Message) {
        case WM_LBUTTONDOWN:
            {
                /* this is a common trick for easy dragging of the window.this message fools windows telling that the user is
                 actually dragging the application caption bar.*/
                 SendMessage(hWnd, WM_NCLBUTTONDOWN, HTCAPTION,NULL);
                break;
            }

        /*case WM_CREATE:
            break;
    */

        case WM_CLOSE:
            PostQuitMessage(0);
            break;

        case WM_DESTROY:
            UnregisterClass(lpszClassName, hInst);
            PostQuitMessage(0);
            break;

        case WM_KEYDOWN:    //KeyBoard keys
            // Which key was pressed?
            switch (wParam) {
                case VK_ESCAPE: //close through escape key
                    PostQuitMessage(0);
                    return 0;
                case VK_RETURN:
                    MessageBox(hWnd, TEXT("DFGDGD"), TEXT("DFGDFG"), NULL);
                    return 0;
            } // End Switch

            break;

        case WM_COMMAND:
            /*switch(LOWORD(wParam))
        {
        }*/
        break;

        case WM_PAINT:
            break;

        default:
            return DefWindowProc(hWnd, Message, wParam, lParam);

    } // End Message Switch

return 0;
};

班级标题:

class CWnd {
    public:
        CWnd();
        CWnd(LPTSTR lpszClassName, LPTSTR lpszWindowName);
        virtual ~CWnd();
        virtual HWND CreateDef(void);           // Create the window with default parameters
        virtual LRESULT     WndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam );

    private:
        static LRESULT CALLBACK StaticWndProc(HWND hWnd, UINT Message, WPARAM wParam, LPARAM lParam);
        HWND        g_hWnd;     //Global window handle for this window
        HINSTANCE   hInst;      //Global instance for this window

        LPTSTR          lpszClassName;
        LPTSTR          lpszWindowName;
};

PS我包含了所有需要的头文件,一切都很好,除了MessageBox

这也是这里代码的链接

Answer 1

Ohhhhhhh最后我找到了这个问题的解决方案......并且让每个人都受益于问题是在WMPAINT的WndProc(.......)消息我在其中编写了一些代码并删除了所有代码以及BeginPaint和EndPaint函数使程序进入冻结期间,一旦任何东西被绘制在它上面,包括MessageBox,但它只显示当我按下Alt我认为coz控件转移到系统的那一步显示系统菜单(我认为)

解决方案是删除WM_PAINT消息处理程序或添加正常的BeginPaint和EndPaint函数

感谢所有传递我问题的人

Answer 2

如果有人仍然感兴趣，此方法有效：

MessageBox(NULL,L"error",L"Error",MB_ICONERROR|MB_DEFAULT_DESKTOP_ONLY);