c++ - EnumChildWindows 中的 MoveWindow 对对话框内 ListView 的影响 : Why ListView Header is not correctly scrolling

Question

我有一个 listview 控件 (lvc)，它位于 DialogBox(dbx) 中，而且 dbx 也有一个垂直滚动条。

每当滚动条滚动时，调用EnumChildWindows 来枚举dbx 的所有子窗口。回调函数包含一个可以移动该 lvc 的 MoveWindow 函数。 lvc 滚动正常但不是它的列标题，它们不随 ListView 移动。

如果我在回调函数中注释掉 MoveWindow 函数，那么什么都不会改变。 (偏离路线的 lvc 不会移动!)这意味着 EnumChildWindow 没有问题，但是回调函数内的 MoveWindow 导致了问题，我确信这是因为调用回调函数外部的 MoveWindow 函数可以正常工作(因为在这个例子中只有一个控件，即 lvc，所以我不需要枚举所有子窗口)。

代码如下:

主要.cpp

#if defined(UNICODE) && !defined(_UNICODE)
    #define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
    #define UNICODE
#endif

#include <tchar.h>
#define _WIN32_IE 0x0700
#include <windows.h>
#include <windowsx.h>
#include <commctrl.h>
#include <vector>
#include "res.h"
#define btn 0
#include <iostream>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
BOOL CALLBACK diaproc(HWND hwmd, UINT msg, WPARAM wp, LPARAM lp);
BOOL CALLBACK edc(HWND hwmd,LPARAM lp);
HINSTANCE gi;
int iPrevVscroll=0;
/*  Make the class name into a global variable  */
TCHAR szClassName[ ] = _T("CodeBlocksWindowsApp");

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    gi = wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS ;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           _T("Code::Blocks Template Windows App"),       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
    case WM_CREATE:
        CreateWindow(WC_BUTTON, "CLICK", WS_CHILD | BS_DEFPUSHBUTTON | WS_VISIBLE, 10, 10, 80, 30, hwnd, (HMENU)btn, gi, NULL  );

    break;
    case WM_COMMAND:{
        if( LOWORD(wParam) == btn && HIWORD(wParam) == BN_CLICKED ) DialogBox(gi, MAKEINTRESOURCE(dia), hwnd,(DLGPROC)diaproc);
        DWORD err = GetLastError();
        std::cout<<err<<std::endl<<dia;
    }
    break;
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}

BOOL CALLBACK diaproc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lp)
{

    static HWND lv_hwnd;
    static int sci;
    switch(msg)
    {
    case WM_INITDIALOG:
        {

            INITCOMMONCONTROLSEX is;
            is.dwSize = sizeof(INITCOMMONCONTROLSEX);
            is.dwICC = ICC_LISTVIEW_CLASSES;
            InitCommonControlsEx(&is);

            int col_fmt[5] = { LVCFMT_CENTER, LVCFMT_LEFT, LVCFMT_CENTER, LVCFMT_CENTER, LVCFMT_CENTER };
            int col_wid[5] = { 30, 90, 50, 30, 70 };
            std::vector<TCHAR*> col_nam(5);
            col_nam[0] = _T("S.No"); col_nam[1] = _T("Description"); col_nam[2] = _T("HSN"); col_nam[3] = _T("QTY"); col_nam[4] = _T("Rate");

            lv_hwnd = CreateWindow(
                                        WC_LISTVIEW,
                                        _T(""),
                                        WS_CHILD | LVS_REPORT | LVS_EDITLABELS | WS_VISIBLE,
                                        10, 0, 300, 200,
                                        hwnd,
                                        NULL,
                                        (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE),
                                        NULL
                                        );
            ListView_SetExtendedListViewStyle(lv_hwnd, LVS_EX_FLATSB | LVS_EX_FULLROWSELECT | LVS_EX_GRIDLINES | LVS_EX_LABELTIP );
            LVCOLUMN lvc;
            lvc.mask = LVCF_FMT | LVCF_SUBITEM | LVCF_WIDTH | LVCF_TEXT;
            for(int i =0; i < 5; i++)
            {
                lvc.fmt = col_fmt[i];
                lvc.cx = col_wid[i];
                lvc.pszText = col_nam[i];
                lvc.iSubItem =  i;
                ListView_InsertColumn(lv_hwnd, i, &lvc);
            }

            SetScrollRange(hwnd, SB_VERT, 0, 225, TRUE);
            SetScrollPos(hwnd, SB_VERT, 0, TRUE);
        } return FALSE;

        case WM_VSCROLL:
        {
            RECT rc; GetWindowRect(lv_hwnd, &rc);
            POINT pt1 = {rc.left, rc.top}; ScreenToClient(hwnd, &pt1);
            POINT pt2 = {rc.right, rc.bottom}; ScreenToClient(hwnd, &pt2);
            std::cout<<"rc.top : "<< rc.top<<"\nrc.bottom: "<< rc.bottom <<"\nrc.right : "<<rc.right<<"\nrc.left : "<<rc.left<<"\n\n";
            std::cout<<"pt1.y : "<< pt1.y<<"\npt2.y: "<< pt2.y<<"\npt2.x : "<<pt2.x<<"\npt1.x : "<<pt1.x<<"\n\n\n";

            switch(LOWORD(wParam))
            {
            case SB_PAGEDOWN:
            case SB_LINEDOWN:
                sci += 10; break;
            case SB_PAGEUP:
            case SB_LINEUP:
                sci -= 10; break;
            case SB_THUMBTRACK:
                sci = HIWORD(wParam); break;
            };
            sci = sci < 0 ? 0 : sci > 225 ? 225 : sci;
            SetScrollPos(hwnd, SB_VERT, sci, FALSE);
            //MoveWindow(lv_hwnd, pt1.x, pt1.y - sci + iPrevVscroll, pt2.x - pt1.x, pt2.y - pt1.y, TRUE);
            EnumChildWindows(hwnd, edc, (LPARAM)sci);
        }; return TRUE;
            case WM_COMMAND:
                if(LOWORD(wParam) == IDCANCEL) EndDialog(hwnd, wParam); return TRUE;

        default: return FALSE;
    }
}

BOOL CALLBACK edc(HWND hwnd, LPARAM lp)
{
    long s = (long) lp;

    RECT rc; GetWindowRect(hwnd, &rc);
    POINT pt1 = {rc.left, rc.top}; ScreenToClient(hwnd, &pt1);
    POINT pt2 = {rc.right, rc.bottom}; ScreenToClient(hwnd, &pt2);
    MoveWindow(hwnd, pt1.x, pt1.y + s - iPrevVscroll, pt2.x - pt1.x, pt2.y - pt1.y, TRUE);

}

资源.h

#define lv 1
#define dia 2

资源.rc

#include <windows.h>
#include <commctrl.h>
#include <richedit.h>
#include "res.h"

dia DIALOGEX 0,0,500,300
CAPTION "New Invoice"
STYLE DS_3DLOOK | DS_CENTER | DS_MODALFRAME | DS_SHELLFONT | WS_CAPTION | WS_VISIBLE | WS_POPUP | WS_SYSMENU | WS_THICKFRAME | WS_VSCROLL

FONT 8, "Ms Shell Dlg"
{

}

在 main.cpp 中，您可以在底部找到 MoveWindow 和其他相关函数。

以下图片很有用。

同样，出于说明的目的，MoveWindow 中的滚动逻辑也是不同的。

当我遇到这个问题时，最初我正在做一个有很多控件的项目。我单独分析了这个，发现我上面写的是什么。虽然我通过采用不同的方法向下滚动所有控件(不包括从 EnumChildWindows 调用 MoveWindow )绕过了这个问题，但我很想知道这个问题的原因和解决方法。

感谢您抽出宝贵时间阅读这篇长篇文章。任何建议或改进也将是惊人的!

Answer 1

来自EnumChildWindows() reference的备注部分:

If a child window has created child windows of its own, EnumChildWindows enumerates those windows as well.

所以您在这里所做的是滚动 ListView 控件，然后分别滚动标题控件。结果是标题控件相对于 ListView 控件移动，如第二张屏幕截图所示。

相反，您应该只移动对话框的直接子项，因为孙子项会自动与他们的父项一起移动。

可能的解决方案:

• 在 EnumChildWindows() 回调中检查父/子关系(例如，通过调用子对象上的 GetParent() 并将其与您的对话框句柄进行比较)。
• 不调用 EnumChildWindows() 和 MoveWindow()，而是使用 SW_SCROLLCHILDREN 调用 ScrollWindowEx()。这是实现滚动的最简单方法，因此我更喜欢这种解决方案。