c++ - PeekMessage 没有收到消息？

Question

我创建了一个自定义消息类型，用于调整我的 Window 的大小，称为 WM_NEED_RESIZE。我已经在我的 .h 文件中定义了它，并在我的 .cpp 文件中进行了初始化。我还注册了我的 WindowProc 函数来接受消息。以下是这些项目的代码:

const uint32 WindowsGLWindow::WM_NEED_RESIZE = WM_USER + 100;
LONG WINAPI WindowsGLWindow::WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    static PAINTSTRUCT ps;// do I need this?
    static sint32 newWidth = 0;
    static sint32 newHeight = 0;
    bool res = false;

    switch (uMsg) {
        case WM_PAINT:
            //display();
            BeginPaint(hWnd, &ps);
            EndPaint(hWnd, &ps);
            return 0;

        case WM_SIZE:
            //glViewport(0, 0, LOWORD(lParam), HIWORD(lParam));
            res = PostMessage(hWnd, WindowsGLWindow::WM_NEED_RESIZE, wParam,     lParam);
            std::cout << "WM_SIZE: " << res << std::endl;
            return 0;

        case WindowsGLWindow::WM_NEED_RESIZE:
            std::cout << "WindowsGLWindow::WM_NEED_RESIZE" << std::endl;
            break;

        case WM_CHAR:
            switch (wParam) {
                case 27: /* ESC key */
                    PostQuitMessage(0);
                    break;
            }
            return 0;

        case WM_CLOSE:
            PostQuitMessage(0);
            return 0;
    }

    return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

在另一个函数中，我通过 PeekMessage(..) 运行以收集所有消息。这是消息泵的片段:

    MSG msg;
    while (PeekMessage(&msg, 0, 0, 0, PM_REMOVE) == TRUE) // maybe use GetInputState(?)     as well?
    {
        if (msg.message == WM_QUIT)
            retVal = -1;

        if (msg.message == WindowsGLWindow::WM_NEED_RESIZE) {
            uint32 newWidth = LOWORD(msg.lParam);
            uint32 newHeight = HIWORD(msg.lParam);

            std::cout << "PeekMessage: WindowsGLWindow::WM_NEED_RESIZE" <<         std::endl;

            // call resize only if our window-size changed
            if ((newWidth != width_) || (newHeight != height_)) {
                resize(newWidth, newHeight);
            }

            PostMessage(msg.hwnd, WM_PAINT, 0, 0);
        }

        switch (msg.message) {
            case WM_MOUSEMOVE:
                // Retrieve mouse screen position
                //int x = (short) LOWORD(lParam);
                //int y = (short) HIWORD(lParam);

                // Check to see if the left button is held down:
                //bool leftButtonDown = wParam & MK_LBUTTON;

                // Check if right button down:
                //bool rightButtonDown = wParam & MK_RBUTTON;
                break;
            case WM_LBUTTONDOWN:
            case WM_RBUTTONDOWN:
            case WM_LBUTTONUP:
            case WM_RBUTTONUP:
            case WM_KEYUP:
            case WM_KEYDOWN:
                /*
                switch (msg.wParam) {
                    case 'W':
                        // w key pressed
                        break;
                    case VK_RIGHT:
                        // Right arrow pressed
                        break;
                    default:
                        break;
                }
                */
                break;
        }

        TranslateMessage(&msg);
        DispatchMessage(&msg);

    }

我的问题是 WM_NEED_RESIZE 消息仅在窗口首次打开时在消息队列中找到 一次 ，此后我再也不会在消息队列中找到它PeekMessage(..)。我真的不确定为什么会这样。但是，它是，由WindowProc(..) 方法接收(这对我没有真正帮助)。如果你们能提供任何帮助，我将不胜感激。

谢谢

贾勒特

Answer 1

1. 不要使用 std::cout 期望在调试器中看到该输出，而是使用 OutputDebugString(); .

2. 您需要将您的类指针传递给调用 CreateWindowEx 的最后一个参数，然后从 WM_CREATE 的 LPARAM 中传递给您的 LPCREATESTRUCT 中检索该指针，您的类指针将位于结构。将类指针设置为窗口的 GWLP_USERDATA，并在任何其他消息调用中调用 GetWindowsLong，检索类指针，然后将消息、wparam 和 lparam 全部传递给内部类消息处理程序。

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http://msdn.microsoft.com/en-us/library/ff381400%28v=VS.85%29.aspx