使用TRUE调用MoveWindow()后，窗口客户区仍然无效

Question

MSDN doc's for MoveWindow() says:

“如果bRepaint参数为TRUE，则系统在移动窗口后立即向窗口过程发送WM_PAINT消息（即MoveWindow函数调用UpdateWindow函数）。”

但是当我在 MoveWindow() 之后调用 GetUpdateRect() 时，在处理父级中的 WM_LBUTTONDOWN 消息时，我得到一个哔哔声，这表明子级无效。什么解释？？？

#include <windows.h>
#include <windowsx.h>
#include <tchar.h>

HINSTANCE   ghInstance;

LRESULT CALLBACK WindowProc (HWND hwnd, UINT message, UINT wParam, LONG lParam);
LRESULT CALLBACK ChildProc (HWND hwnd, UINT message, UINT wParam, LONG lParam);

int APIENTRY WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
    HWND        hWnd;
    MSG     msg;
    WNDCLASSEX  wndclassx;

    ghInstance = hInstance;

    wndclassx.cbSize        = sizeof(WNDCLASSEX);
    wndclassx.style         = 0;
    wndclassx.lpfnWndProc   = WindowProc;
    wndclassx.cbClsExtra    = 0;
    wndclassx.cbWndExtra    = 0;
    wndclassx.hInstance     = hInstance;
    wndclassx.hIcon         = 0;
    wndclassx.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wndclassx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclassx.lpszMenuName  = NULL;
    wndclassx.lpszClassName = _T("ParentWindow");
    wndclassx.hIconSm       = NULL;

    if( !RegisterClassEx(&wndclassx) ) return 0;

    wndclassx.cbSize        = sizeof(WNDCLASSEX);
    wndclassx.style         = 0;
    wndclassx.lpfnWndProc   = ChildProc;
    wndclassx.cbClsExtra    = 0;
    wndclassx.cbWndExtra    = 0;
    wndclassx.hInstance     = hInstance;
    wndclassx.hIcon         = 0;
    wndclassx.hCursor       = 0;
    wndclassx.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclassx.lpszMenuName  = NULL;
    wndclassx.lpszClassName = _T("ChildWindow");
    wndclassx.hIconSm       = NULL;

    if( !RegisterClassEx(&wndclassx) ) return 0;

    if( !(hWnd = CreateWindow(_T("ParentWindow"), _T("Parent Window"), WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN,
                              CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance,
                              NULL)) ) return 0;

    ShowWindow(hWnd, SW_SHOW);
    UpdateWindow(hWnd);

    while( GetMessage(&msg, NULL, 0, 0) )
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return (int)msg.wParam;
}

LRESULT CALLBACK WindowProc (HWND hwnd, UINT message, UINT wParam, LONG lParam)
{
    HWND    hWnd;

    switch ( message )
    {
        case WM_CREATE:

        CreateWindow(_T("ChildWindow"), NULL, WS_CHILD | WS_VISIBLE | WS_BORDER, 10, 10, 100, 100, hwnd, (HMENU)0,
                          ghInstance, NULL);
        break;

        case WM_LBUTTONDOWN:

        hWnd = GetWindow(hwnd, GW_CHILD);

        MoveWindow(hWnd, 10, 10, 200, 200, true);

        if( GetUpdateRect(hWnd, NULL, FALSE) ) MessageBeep(-1);
        break;

        case WM_DESTROY:
        PostQuitMessage(0);
        break;

        default:

        return DefWindowProc(hwnd, message, wParam, lParam);
    }
    return 0;
}

LRESULT CALLBACK ChildProc (HWND hwnd, UINT message, UINT wParam, LONG lParam)
{
    return DefWindowProc(hwnd, message, wParam, lParam);
}

Answer 1

MSDN 文档是错误的。如文档所述，带有 TRUE 的 MoveWindow() 不会调用 UpdateWindow()。它只是使窗口客户区无效。如果我在 MoveWindow() 之后调用 UpdateWindow()，程序会按预期运行。

Answer 2

我自己尝试过，WM_PAINT 在if(GetUpdateRect()) 之前被触发。另外，GetUpdateRect 为我返回 FALSE。 我在 XP 上运行 Visual Studio 2008。 我想这可能取决于您使用的编译器，使用的操作系统等等。根据你传递的代码，一切都是在同一个线程中完成的，但如果它是一个多线程程序，我认为这也会造成一些问题。