c - 我的自定义 ListView 控件中发生了什么导致滚动时部分或完全不重新绘制行？

Question

我正在构建一个自定义 ListView 控件，因为标准 comctl32.dll 控件不能充分满足我的需求。到目前为止，除了滚动之外，一切似乎进展顺利。

起初，事情看起来像这样(在 wine 下，但真实的 Windows 也会受到影响)；

损坏的形式根据所使用的滚动类型而变化。如果我使用鼠标滚轮滚动，每隔几行就会损坏:

如果我通过拖动拇指滚动，就会发生这种情况:

在这两种情况下，单击某处都会重新绘制所有内容，并且损坏就会消失。

我不太确定我在这里做错了什么。

这是代码；我将在下面解释它是如何工作的:

// 19 october 2014
#define UNICODE
#define _UNICODE
#define STRICT
#define STRICT_TYPED_ITEMIDS
// get Windows version right; right now Windows XP
#define WINVER 0x0501
#define _WIN32_WINNT 0x0501
#define _WIN32_WINDOWS 0x0501       /* according to Microsoft's winperf.h */
#define _WIN32_IE 0x0600            /* according to Microsoft's sdkddkver.h */
#define NTDDI_VERSION 0x05010000    /* according to Microsoft's sdkddkver.h */
#include <windows.h>
#include <commctrl.h>
#include <stdint.h>
#include <uxtheme.h>
#include <string.h>
#include <wchar.h>
#include <windowsx.h>
#include <vsstyle.h>
#include <vssym32.h>

// #qo LIBS: user32 kernel32 gdi32 comctl32

// TODO
// - http://blogs.msdn.com/b/oldnewthing/archive/2003/09/09/54826.aspx (relies on the integrality parts? IDK)
//  - might want to http://blogs.msdn.com/b/oldnewthing/archive/2003/09/17/54944.aspx instead
// - http://msdn.microsoft.com/en-us/library/windows/desktop/bb775574%28v=vs.85%29.aspx
// - hscroll (harder)
//  - keyboard navigation
//  - mousewheel navigation

#define tableWindowClass L"gouitable"

struct table {
    HWND hwnd;
    HFONT defaultFont;
    HFONT font;
    intptr_t selected;
    intptr_t count;
    intptr_t firstVisible;
    intptr_t pagesize;      // in rows
    int wheelCarry;
    HWND header;
    int headerHeight;
    intptr_t nColumns;
    HIMAGELIST imagelist;
    int imagelistHeight;
};

static LONG rowHeight(struct table *t)
{
    HFONT thisfont, prevfont;
    TEXTMETRICW tm;
    HDC dc;
    LONG ret;

    dc = GetDC(t->hwnd);
    if (dc == NULL)
        abort();
    thisfont = t->font;     // in case WM_SETFONT happens before we return
    prevfont = (HFONT) SelectObject(dc, thisfont);
    if (prevfont == NULL)
        abort();
    if (GetTextMetricsW(dc, &tm) == 0)
        abort();
    if (SelectObject(dc, prevfont) != (HGDIOBJ) (thisfont))
        abort();
    if (ReleaseDC(t->hwnd, dc) == 0)
        abort();
    ret = tm.tmHeight;
    if (ret < t->imagelistHeight)
        ret = t->imagelistHeight;
    return ret;
}

static void redrawAll(struct table *t)
{
    if (InvalidateRect(t->hwnd, NULL, TRUE) == 0)
        abort();
    if (UpdateWindow(t->hwnd) == 0)
        abort();
}

static RECT realClientRect(struct table *t)
{
    RECT r;

    if (GetClientRect(t->hwnd, &r) == 0)
        abort();
    r.top += t->headerHeight;
    return r;
}

static void recomputeHScroll(struct table *t)
{
    HDITEMW item;
    intptr_t i;
    int width = 0;
    RECT r;
    SCROLLINFO si;

    // TODO count dividers
    for (i = 0; i < t->nColumns; i++) {
        ZeroMemory(&item, sizeof (HDITEMW));
        item.mask = HDI_WIDTH;
        if (SendMessageW(t->header, HDM_GETITEM, (WPARAM) i, (LPARAM) (&item)) == FALSE)
            abort();
        width += item.cxy;
    }

    if (GetClientRect(t->hwnd, &r) == 0)
        abort();
    ZeroMemory(&si, sizeof (SCROLLINFO));
    si.cbSize = sizeof (SCROLLINFO);
    si.fMask = SIF_PAGE | SIF_RANGE;
    si.nPage = r.right - r.left;
    si.nMin = 0;
    si.nMax = width - 1;            // - 1 because endpoints inclusive
    SetScrollInfo(t->hwnd, SB_HORZ, &si, TRUE);
}

static void finishSelect(struct table *t)
{
    if (t->selected < 0)
        t->selected = 0;
    if (t->selected >= t->count)
        t->selected = t->count - 1;
    // TODO update only the old and new selected items
    redrawAll(t);
    // TODO scroll to the selected item if it's not entirely visible
}

static void keySelect(struct table *t, WPARAM wParam, LPARAM lParam)
{
    // TODO figure out correct behavior with nothing selected
    if (t->count == 0)      // don't try to do anything if there's nothing to do
        return;
    switch (wParam) {
    case VK_UP:
        t->selected--;
        break;
    case VK_DOWN:
        t->selected++;
        break;
    case VK_PRIOR:
        t->selected -= t->pagesize;
        break;
    case VK_NEXT:
        t->selected += t->pagesize;
        break;
    case VK_HOME:
        t->selected = 0;
        break;
    case VK_END:
        t->selected = t->count - 1;
        break;
    default:
        // don't touch anything
        return;
    }
    finishSelect(t);
}

static void selectItem(struct table *t, WPARAM wParam, LPARAM lParam)
{
    int x, y;
    LONG h;

    x = GET_X_LPARAM(lParam);
    y = GET_Y_LPARAM(lParam);
    h = rowHeight(t);
    y += t->firstVisible * h;
    y -= t->headerHeight;
    y /= h;
    t->selected = y;
    if (t->selected >= t->count)
        t->selected = -1;
    finishSelect(t);
}

// TODO on initial show the items are not arranged properly
// TODO the lowest visible row does not redraw properly after scrolling
// TODO the row behind the header bar does not redraw properly after scrolling
static void vscrollto(struct table *t, intptr_t newpos)
{
    SCROLLINFO si;
    RECT scrollArea;

    if (newpos < 0)
        newpos = 0;
    if (newpos > (t->count - t->pagesize))
        newpos = (t->count - t->pagesize);

    scrollArea = realClientRect(t);

    // negative because ScrollWindowEx() is "backwards"
    if (ScrollWindowEx(t->hwnd, 0, (-(newpos - t->firstVisible)) * rowHeight(t),
        &scrollArea, &scrollArea, NULL, NULL,
        SW_ERASE | SW_INVALIDATE) == ERROR)
        abort();
    t->firstVisible = newpos;

    ZeroMemory(&si, sizeof (SCROLLINFO));
    si.cbSize = sizeof (SCROLLINFO);
    si.fMask = SIF_PAGE | SIF_POS | SIF_RANGE;
    si.nPage = t->pagesize;
    si.nMin = 0;
    si.nMax = t->count - 1;     // nMax is inclusive
    si.nPos = t->firstVisible;
    SetScrollInfo(t->hwnd, SB_VERT, &si, TRUE);
}

static void vscrollby(struct table *t, intptr_t n)
{
    vscrollto(t, t->firstVisible + n);
}

static void wheelscroll(struct table *t, WPARAM wParam)
{
    int delta;
    int lines;
    UINT scrollAmount;

    delta = GET_WHEEL_DELTA_WPARAM(wParam);
    if (SystemParametersInfoW(SPI_GETWHEELSCROLLLINES, 0, &scrollAmount, 0) == 0)
        abort();
    if (scrollAmount == WHEEL_PAGESCROLL)
        scrollAmount = t->pagesize;
    if (scrollAmount == 0)      // no mouse wheel scrolling (or t->pagesize == 0)
        return;
    // the rest of this is basically http://blogs.msdn.com/b/oldnewthing/archive/2003/08/07/54615.aspx and http://blogs.msdn.com/b/oldnewthing/archive/2003/08/11/54624.aspx
    // see those pages for information on subtleties
    delta += t->wheelCarry;
    lines = delta * ((int) scrollAmount) / WHEEL_DELTA;
    t->wheelCarry = delta - lines * WHEEL_DELTA / ((int) scrollAmount);
    vscrollby(t, -lines);
}

static void vscroll(struct table *t, WPARAM wParam)
{
    SCROLLINFO si;
    intptr_t newpos;

    ZeroMemory(&si, sizeof (SCROLLINFO));
    si.cbSize = sizeof (SCROLLINFO);
    si.fMask = SIF_POS | SIF_TRACKPOS;
    if (GetScrollInfo(t->hwnd, SB_VERT, &si) == 0)
        abort();

    newpos = t->firstVisible;
    switch (LOWORD(wParam)) {
    case SB_TOP:
        newpos = 0;
        break;
    case SB_BOTTOM:
        newpos = t->count - t->pagesize;
        break;
    case SB_LINEUP:
        newpos--;
        break;
    case SB_LINEDOWN:
        newpos++;
        break;
    case SB_PAGEUP:
        newpos -= t->pagesize;
        break;
    case SB_PAGEDOWN:
        newpos += t->pagesize;
        break;
    case SB_THUMBPOSITION:
        newpos = (intptr_t) (si.nPos);
        break;
    case SB_THUMBTRACK:
        newpos = (intptr_t) (si.nTrackPos);
    }

    vscrollto(t, newpos);
}

static void resize(struct table *t)
{
    RECT r;
    SCROLLINFO si;
    HDLAYOUT headerlayout;
    WINDOWPOS headerpos;

    // do this first so our scrollbar calculations can be correct
    if (GetClientRect(t->hwnd, &r) == 0)        // use the whole client rect
        abort();
    headerlayout.prc = &r;
    headerlayout.pwpos = &headerpos;
    if (SendMessageW(t->header, HDM_LAYOUT, 0, (LPARAM) (&headerlayout)) == FALSE)
        abort();
    if (SetWindowPos(t->header, headerpos.hwndInsertAfter, headerpos.x, headerpos.y, headerpos.cx, headerpos.cy, headerpos.flags | SWP_SHOWWINDOW) == 0)
        abort();
    t->headerHeight = headerpos.cy;

    // now adjust the scrollbars
    r = realClientRect(t);
    t->pagesize = (r.bottom - r.top) / rowHeight(t);
    ZeroMemory(&si, sizeof (SCROLLINFO));
    si.cbSize = sizeof (SCROLLINFO);
    si.fMask = SIF_RANGE | SIF_PAGE;
    si.nMin = 0;
    si.nMax = t->count - 1;
    si.nPage = t->pagesize;
    SetScrollInfo(t->hwnd, SB_VERT, &si, TRUE);

    recomputeHScroll(t);
}

static void drawItems(struct table *t, HDC dc, RECT cliprect)
{
    HFONT thisfont, prevfont;
    LONG height;
    LONG y;
    intptr_t i;
    RECT controlSize;       // for filling the entire selected row
    intptr_t first, last;
    POINT prevOrigin, prevViewportOrigin;

    if (GetClientRect(t->hwnd, &controlSize) == 0)
        abort();

    height = rowHeight(t);

    thisfont = t->font;     // in case WM_SETFONT happens before we return
    prevfont = (HFONT) SelectObject(dc, thisfont);
    if (prevfont == NULL)
        abort();

    // adjust the clip rect and the window so that (0, 0) is always the first item
    // adjust the viewport so that everything is shifted down t->headerHeight pixels
    if (OffsetRect(&cliprect, 0, t->firstVisible * height) == 0)
        abort();
    if (GetWindowOrgEx(dc, &prevOrigin) == 0)
        abort();
    if (SetWindowOrgEx(dc, prevOrigin.x, prevOrigin.y + (t->firstVisible * height), NULL) == 0)
        abort();
    if (SetViewportOrgEx(dc, 0, t->headerHeight, &prevViewportOrigin) == 0)
        abort();

    // see http://blogs.msdn.com/b/oldnewthing/archive/2003/07/29/54591.aspx and http://blogs.msdn.com/b/oldnewthing/archive/2003/07/30/54600.aspx
    first = cliprect.top / height;
    if (first < 0)
        first = 0;
    last = (cliprect.bottom + height - 1) / height;
    if (last >= t->count)
        last = t->count;

    y = first * height;
    for (i = first; i < last; i++) {
        RECT rsel;
        HBRUSH background;
        int textColor;
        WCHAR msg[100];
        RECT headeritem;
        intptr_t j;
        LRESULT xoff;

        // TODO verify these two
        background = (HBRUSH) (COLOR_WINDOW + 1);
        textColor = COLOR_WINDOWTEXT;
        if (t->selected == i) {
            // these are the colors wine uses (http://source.winehq.org/source/dlls/comctl32/listview.c)
            // the two for unfocused are also suggested by http://stackoverflow.com/questions/10428710/windows-forms-inactive-highlight-color
            background = (HBRUSH) (COLOR_HIGHLIGHT + 1);
            textColor = COLOR_HIGHLIGHTTEXT;
            if (GetFocus() != t->hwnd) {
                background = (HBRUSH) (COLOR_BTNFACE + 1);
                textColor = COLOR_BTNTEXT;
            }
        }

        // first fill the selection rect
        rsel.left = controlSize.left;
        rsel.top = y;
        rsel.right = controlSize.right - controlSize.left;
        rsel.bottom = y + height;
        if (FillRect(dc, &rsel, background) == 0)
            abort();

        xoff = SendMessageW(t->header, HDM_GETBITMAPMARGIN, 0, 0);

        // now draw the cells
        if (SetTextColor(dc, GetSysColor(textColor)) == CLR_INVALID)
            abort();
        if (SetBkMode(dc, TRANSPARENT) == 0)
            abort();
        for (j = 0; j < t->nColumns; j++) {
            if (SendMessageW(t->header, HDM_GETITEMRECT, (WPARAM) j, (LPARAM) (&headeritem)) == 0)
                abort();

            if (j == 1) {           // TODO
                IMAGELISTDRAWPARAMS ip;

                ZeroMemory(&ip, sizeof (IMAGELISTDRAWPARAMS));
                ip.cbSize = sizeof (IMAGELISTDRAWPARAMS);
                ip.himl = t->imagelist;
                ip.i = 0;
                ip.hdcDst = dc;
                ip.x = headeritem.left + xoff;
                ip.y = y;
                ip.cx = 0;      // draw whole image
                ip.cy = 0;
                ip.xBitmap = 0;
                ip.yBitmap = 0;
                ip.rgbBk = CLR_NONE;
                ip.fStyle = ILD_NORMAL | ILD_SCALE;     // TODO alpha-blend; ILD_DPISCALE?
                // TODO ILS_ALPHA?
                if (ImageList_DrawIndirect(&ip) == 0)
                    abort();
                continue;
            }
            rsel.left = headeritem.left + xoff;
            rsel.top = y;
            rsel.right = headeritem.right;
            rsel.bottom = y + height;
            // TODO vertical center in case the height is less than the icon height?
            if (DrawTextExW(dc, msg, wsprintf(msg, L"Item %d", i), &rsel, DT_END_ELLIPSIS | DT_LEFT | DT_NOPREFIX | DT_SINGLELINE, NULL) == 0)
                abort();
        }
        y += height;
    }

    // reset everything
    if (SetViewportOrgEx(dc, prevViewportOrigin.x, prevViewportOrigin.y, NULL) == 0)
        abort();
    if (SetWindowOrgEx(dc, prevOrigin.x, prevOrigin.y, NULL) == 0)
        abort();
    if (SelectObject(dc, prevfont) != (HGDIOBJ) (thisfont))
        abort();
}

static LRESULT CALLBACK tableWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    struct table *t;
    HDC dc;
    PAINTSTRUCT ps;
    NMHDR *nmhdr = (NMHDR *) lParam;
    NMHEADERW *nm = (NMHEADERW *) lParam;

    t = (struct table *) GetWindowLongPtrW(hwnd, GWLP_USERDATA);
    if (t == NULL) {
        // we have to do things this way because creating the header control will fail mysteriously if we create it first thing
        // (which is fine; we can get the parent hInstance this way too)
        if (uMsg == WM_NCCREATE) {
            CREATESTRUCTW *cs = (CREATESTRUCTW *) lParam;

            t = (struct table *) malloc(sizeof (struct table));
            if (t == NULL)
                abort();
            ZeroMemory(t, sizeof (struct table));
            t->hwnd = hwnd;
            // TODO this should be a global
            t->defaultFont = (HFONT) GetStockObject(SYSTEM_FONT);
            if (t->defaultFont == NULL)
                abort();
            t->font = t->defaultFont;
t->selected = 5;t->count=100;//TODO
            t->header = CreateWindowExW(0,
                WC_HEADERW, L"",
                // TODO is HOTTRACK needed?
                WS_CHILD | HDS_FULLDRAG | HDS_HORZ | HDS_HOTTRACK,
                0, 0, 0, 0,
                t->hwnd, (HMENU) 100, cs->hInstance, NULL);
            if (t->header == NULL)
                abort();
{HDITEMW item;
ZeroMemory(&item, sizeof (HDITEMW));
item.mask = HDI_WIDTH | HDI_TEXT | HDI_FORMAT;
item.cxy = 200;
item.pszText = L"Column";
item.fmt = HDF_LEFT | HDF_STRING;
if (SendMessage(t->header, HDM_INSERTITEM, 0, (LPARAM) (&item)) == (LRESULT) (-1))
abort();
ZeroMemory(&item, sizeof (HDITEMW));
item.mask = HDI_WIDTH | HDI_TEXT | HDI_FORMAT;
item.cxy = 150;
item.pszText = L"Column 2";
item.fmt = HDF_LEFT | HDF_STRING;
if (SendMessage(t->header, HDM_INSERTITEM, 1, (LPARAM) (&item)) == (LRESULT) (-1))
abort();
t->nColumns=2;
t->imagelist = ImageList_Create(GetSystemMetrics(SM_CXSMICON), GetSystemMetrics(SM_CYSMICON), ILC_COLOR32, 1, 1);
if(t->imagelist==NULL)abort();
{
HICON icon;
int unused;
icon = LoadIconW(NULL, IDI_ERROR);
if(icon == NULL)abort();
if (ImageList_AddIcon(t->imagelist, icon) == -1)abort();
if (ImageList_GetIconSize(t->imagelist, &unused, &(t->imagelistHeight)) == 0)abort();
}
}
            SetWindowLongPtrW(hwnd, GWLP_USERDATA, (LONG_PTR) t);
        }
        // even if we did the above, fall through
        return DefWindowProcW(hwnd, uMsg, wParam, lParam);
    }
    switch (uMsg) {
    case WM_PAINT:
        dc = BeginPaint(hwnd, &ps);
        if (dc == NULL)
            abort();
        drawItems(t, dc, ps.rcPaint);
        EndPaint(hwnd, &ps);
        return 0;
    case WM_SETFONT:
        t->font = (HFONT) wParam;
        if (t->font == NULL)
            t->font = t->defaultFont;
        // also set the header font
        SendMessageW(t->header, WM_SETFONT, wParam, lParam);
        if (LOWORD(lParam) != FALSE) {
            // the scrollbar page size will change so redraw that too
            // also recalculate the header height
            // TODO do that when this is FALSE too somehow
            resize(t);
            redrawAll(t);
        }
        return 0;
    case WM_GETFONT:
        return (LRESULT) t->font;
    case WM_VSCROLL:
        vscroll(t, wParam);
        return 0;
    case WM_MOUSEWHEEL:
        wheelscroll(t, wParam);
        return 0;
    case WM_SIZE:
        resize(t);
        return 0;
    case WM_LBUTTONDOWN:
        selectItem(t, wParam, lParam);
        return 0;
    case WM_SETFOCUS:
    case WM_KILLFOCUS:
        // all we need to do here is redraw the highlight
        // TODO localize to just the selected item
        // TODO ensure giving focus works right
        redrawAll(t);
        return 0;
    case WM_KEYDOWN:
        keySelect(t, wParam, lParam);
        return 0;
    // TODO header double-click
    case WM_NOTIFY:
        if (nmhdr->hwndFrom == t->header)
            switch (nmhdr->code) {
            // I could use HDN_TRACK but wine doesn't emit that
            case HDN_ITEMCHANGING:
            case HDN_ITEMCHANGED:       // TODO needed?
                recomputeHScroll(t);
                redrawAll(t);
                return FALSE;
            }
        // otherwise fall through
    default:
        return DefWindowProcW(hwnd, uMsg, wParam, lParam);
    }
    abort();
    return 0;       // unreached
}

void makeTableWindowClass(void)
{
    WNDCLASSW wc;

    ZeroMemory(&wc, sizeof (WNDCLASSW));
    wc.lpszClassName = tableWindowClass;
    wc.lpfnWndProc = tableWndProc;
    wc.hCursor = LoadCursorW(NULL, IDC_ARROW);
    wc.hIcon = LoadIconW(NULL, IDI_APPLICATION);
    wc.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);     // TODO correct?
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.hInstance = GetModuleHandle(NULL);
    if (RegisterClassW(&wc) == 0)
        abort();
}

int main(void)
{
    HWND mainwin;
    MSG msg;
    INITCOMMONCONTROLSEX icc;

    ZeroMemory(&icc, sizeof (INITCOMMONCONTROLSEX));
    icc.dwSize = sizeof (INITCOMMONCONTROLSEX);
    icc.dwICC = ICC_LISTVIEW_CLASSES;
    if (InitCommonControlsEx(&icc) == 0)
        abort();
    makeTableWindowClass();
    mainwin = CreateWindowExW(0,
        tableWindowClass, L"Main Window",
        WS_OVERLAPPEDWINDOW | WS_HSCROLL | WS_VSCROLL,
        CW_USEDEFAULT, CW_USEDEFAULT,
        400, 400,
        NULL, NULL, GetModuleHandle(NULL), NULL);
    if (mainwin == NULL)
        abort();
    ShowWindow(mainwin, SW_SHOWDEFAULT);
    if (UpdateWindow(mainwin) == 0)
        abort();
    while (GetMessageW(&msg, NULL, 0, 0) > 0) {
        TranslateMessage(&msg);
        DispatchMessageW(&msg);
    }
    return 0;
}

t->firstVisible是第一个可见行； t->pagesize是每个 vscroll 页的行数，并且 t->headerHeight是标题控件的高度(以像素为单位)。 t->wheelcarry是鼠标滚轮遗留物，由此而来。

行的实际高度由 rowHeight() 计算得出函数，其中vscrollto() ，实际调用 ScrolLWindow() 的例程，乘以新的 t->firstVisible通过 计算出要滚动的像素数。

realClientRect() vscrollto()中的逻辑是为了确保只有内容区域滚动，而不是标题控件。

对于绘图，我更改窗口原点以使 (0, 0) 成为第一个项目(第 0 行)，然后更改视口(viewport)原点以考虑标题。 MSDN 的读者会注意到，这听起来很奇怪(SetWindowOrgEx() 和 SetViewportOrgEx() 的文档说您通常不会同时使用两者)，但事实证明，我手动计算标题高度的尝试是灾难性的。

同样，这种情况在真正的 Windows(今天早些时候在 Windows 7 上做过)和 wine 上都会发生。

我做错了什么？谢谢。

Answer 1

我已经尝试过您的代码，我认为问题肯定是由您修改视口(viewport)和窗口原点引起的。问题是，像这样调整原点会改变新绘图在窗口中出现的位置，但不会导致更新区域发生移动。

因此，当只有部分无效区域时(如滚动时所看到的那样)，部分绘图会被更新区域剪掉。

它实际上并不是滚动所特有的 - 您也可以通过将窗口拖离屏幕底部，然后慢慢将其拖回到 View 中来看到相同的效果。窗口最终将完全空白。如果您注释掉对 SetViewportOrgEx 的调用，问题就会完全消失。

您也可以通过调整剪切区域来解决这个问题 - 您必须获取当前的更新区域，将其移动相同的偏移量，然后将其重新选择到 DC 中。或者，您可以重新设计绘画代码，以便在绘画时考虑标题的高度，而不是移动视口(viewport)偏移。您提到您在执行此操作时遇到了其他问题 - 我怀疑解决这些问题比您想象的要容易(即，它看起来有点像 XY 问题)。