Question

写一个小的怀旧爆炸程序，显示一个图标资源库。以下是代码的相关部分，因为我需要在提出问题之前先显示它：

void addGroup(HWND listview, char *name, int id)
{
    LVGROUP g;
    LRESULT n;
    TCHAR *wname;

    ZeroMemory(&g, sizeof (LVGROUP));
    g.cbSize = sizeof (LVGROUP);
    g.mask = LVGF_HEADER | LVGF_GROUPID;
    wname = toWideString(name);
    g.pszHeader = wname;
    // for some reason the group ID and the index returned by LVM_INSERTGROUP are separate concepts... so we have to provide an ID.
    // (thanks to roxfan in irc.efnet.net/#winprog for confirming)
    g.iGroupId = id;
    n = SendMessage(listview, LVM_INSERTGROUP,
        (WPARAM) -1, (LPARAM) &g);
    if (n == (LRESULT) -1)
        panic("error adding list view group \"%s\"", name);
    free(wname);        // list views copy the name (thanks maztheman in irc.freenode.net/#winapi)
}

void buildUI(HWND mainwin)
{
#define CSTYLE (WS_CHILD | WS_VISIBLE)
#define CXSTYLE (0)
#define SETFONT(hwnd) SendMessage(hwnd, WM_SETFONT, (WPARAM) controlfont, (LPARAM) TRUE);

    listview = CreateWindowEx(CXSTYLE,
        WC_LISTVIEW, L"",
        LVS_ICON | WS_VSCROLL | CSTYLE,
        0, 0, 100, 100,
        mainwin, NULL, hInstance, NULL);
    if (listview == NULL)
        panic("error creating list view");

    int itemid = 0;

    // we need to have an item to be able to add a group
    LVITEM dummy;

    ZeroMemory(&dummy, sizeof (LVITEM));
    dummy.mask = LVIF_TEXT;
    dummy.pszText = L"dummy";
    dummy.iItem = itemid++;
    if (SendMessage(listview, LVM_INSERTITEM,
        0, (LPARAM) &dummy) == (LRESULT) -1)
        panic("error adding dummy item to list view");
    // the dummy item has index 0

    HIMAGELIST icons;

    icons = ImageList_Create(32, 32, ILC_COLOR32, 100, 100);
    if (icons == NULL)
        panic("error creating icon list for list view");
    if (SendMessage(listview, LVM_SETIMAGELIST,
        LVSIL_NORMAL, (LPARAM) icons) == (LRESULT) NULL)
;//     panic("error giving icon list to list view");

    if (SendMessage(listview, LVM_ENABLEGROUPVIEW,
        (WPARAM) TRUE, (LPARAM) NULL) == (LRESULT) -1)
        panic("error enabling groups in list view");

    DIR *dir;
    int groupid = 0;

    dir = opendir(dirname);
    if (dir == NULL)
        panic("error opening \"%s\": %s", dirname, strerror(errno));
    for (;;) {
        struct dirent *entry;
        char *filename;
        TCHAR *wfilename;

        errno = 0;
        entry = readdir(dir);
        if (entry == NULL) {
            if (errno != 0)
                panic("error reading \"%s\": %s", dirname, strerror(errno));
            break;      // otherwise, we're done
        }

        if (asprintf(&filename, "%s\\%s", dirname, entry->d_name) == -1)
            panic("error allocating combined filename %s\\%s: %s",
                dirname, entry->d_name, strerror(errno));
        wfilename = toWideString(filename);
        free(filename);

        UINT i, nIcons;

        addGroup(listview, entry->d_name, groupid);

        nIcons = (UINT) ExtractIcon(hInstance, wfilename, -1);
        // no need to check for no icons; nothing will happen
        for (i = 0; i < nIcons; i++) {
            HICON icon;
            int index;

            icon = ExtractIcon(hInstance, wfilename, i);
            if (icon == NULL || icon == (HICON) 1)      // NULL if no icons; 1 if cannot hold icons
                break;
            index = ImageList_AddIcon(icons, icon);
            if (index == -1)
                panic("error adding icon %u from %s to image list", i, entry->d_name);

            LVITEM item;

            ZeroMemory(&item, sizeof (LVITEM));
            item.mask = LVIF_IMAGE | LVIF_GROUPID | LVIF_TEXT;
            item.iImage = index;
            item.iGroupId = groupid;
            char *q;
            asprintf(&q, "%d", itemid);
            item.pszText = toWideString(q);
            free(q);
            item.iItem = itemid++;
            if (SendMessage(listview, LVM_INSERTITEM,
                (WPARAM) -1, (LPARAM) &item) == (LRESULT) -1)
                panic("error adding icon %u from %s to list view", i, entry->d_name);
        }
        free(wfilename);
        groupid++;
    }
    closedir(dir);

    // and we're done with the dummy item
    if (SendMessage(listview, LVM_DELETEITEM, 0, 0) == FALSE)
        panic("error removing dummy item from list view");
}

（假设toWideString()调用malloc()。）虚拟项目用于满足LVM_INSERTGROUP的要求，即列表视图不为空。但是，我的行为很奇怪：

如果我取出LVM_ENABLEGROUPVIEW但保留LVM_DELETEITEM，则虚拟项目会显示在列表顶部，而我添加的最后一项不会出现
如果我取出LVM_ENABLEGROUPVIEW但取出LVM_DELETEITEM，则不显示虚拟项目，并显示我添加的最后一项，但它出现在列表的顶部，而不是底部
- 并且在某些情况下，额外的项目也可能出现在列表的底部！例如，如果扫描C:\Windows\System32
如果我保留LVM_ENABLEGROUPVIEIW，无论我是否保留LVM_DELETEITEM，虚拟项目都不会出现，列表的最后一项显示在它应该的位置
- 我没有检查在这种情况下是否显示额外的图标
请参阅以下更新

有谁可以解释发生了什么？下面列出了一个完整的程序，但目前它依赖于MinGW（我稍后可能会改变）。感谢。

// pietro gagliardi 1 may 2014
// scratch Windows program by pietro gagliardi 17 april 2014
// fixed typos and added toWideString() 1 may 2014
// borrows code from the scratch GTK+ program (16-17 april 2014) and from code written 31 march 2014 and 11-12 april 2014
#define _UNICODE
#define UNICODE
#define STRICT
#define _GNU_SOURCE     // needed to declare asprintf()/vasprintf()
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <getopt.h>
#include <windows.h>
#include <commctrl.h>       // needed for InitCommonControlsEx() (thanks Xeek in irc.freenode.net/#winapi for confirming)
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>

#ifdef  _MSC_VER
#error sorry! the scratch windows program relies on mingw-only functionality! (specifically: asprintf(), getopt_long_only(), directory reading facilities)
#endif

// cheating: we store the help string in the flag argument, collect them, then overwrite them with NULL in init() so getopt_long_only() will return val and not overwrite a string (apparently I'm not the first to think of this: GerbilSoft says GNU tools do this too)
#define flagBool(name, help, short) { name, no_argument, (int *) help, short }
#define flagString(name, help, short) { name, required_argument, (int *) help, short }
static struct option flags[] = {
    // place other options here
    flagBool("help", "show help and quit", 'h'),
    { 0, 0, 0, 0 },
};

HMODULE hInstance;
HICON hDefaultIcon;
HCURSOR hDefaultCursor;
HFONT controlfont;

void panic(char *fmt, ...);
TCHAR *toWideString(char *what);

void init(int argc, char *argv[]);

char *dirname = NULL;

char *args = "dir";     // other command-line arguments here, if any

BOOL parseArgs(int argc, char *argv[])
{
//  if (optind != argc - 1)     // equivalent to argc != 2
//      return FALSE;
//  dirname = argv[optind];
dirname = "C:\\Windows\\System32";
    return TRUE;
}

HWND listview = NULL;

LRESULT CALLBACK wndproc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
    switch (msg) {
    case WM_CLOSE:
        PostQuitMessage(0);
        return 0;
    case WM_SIZE:
        if (listview != NULL) {
            RECT r;

            if (GetClientRect(hwnd, &r) == 0)
                panic("error getting new list view size");
            if (MoveWindow(listview, 0, 0, r.right - r.left, r.bottom - r.top, TRUE) == 0)
                panic("error resizing list view");
        }
        return 0;
    default:
        return DefWindowProc(hwnd, msg, wparam, lparam);
    }
    panic("oops: message %ud does not return anything; bug in wndproc()", msg);
}

HWND makeMainWindow(void)
{
    WNDCLASS cls;
    HWND hwnd;

    ZeroMemory(&cls, sizeof (WNDCLASS));
    cls.lpszClassName = L"mainwin";
    cls.lpfnWndProc = wndproc;
    cls.hInstance = hInstance;
    cls.hIcon = hDefaultIcon;
    cls.hCursor = hDefaultCursor;
    cls.hbrBackground = (HBRUSH) (COLOR_BTNFACE + 1);
    if (RegisterClass(&cls) == 0)
        panic("error registering window class");
    hwnd = CreateWindowEx(0,
        L"mainwin", L"Main Window",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT,
        CW_USEDEFAULT, CW_USEDEFAULT,
        NULL, NULL, hInstance, NULL);
    if (hwnd == NULL)
        panic("opening main window failed");
    return hwnd;
}

void addGroup(HWND listview, char *name, int id)
{
    LVGROUP g;
    LRESULT n;
    TCHAR *wname;

    ZeroMemory(&g, sizeof (LVGROUP));
    g.cbSize = sizeof (LVGROUP);
    g.mask = LVGF_HEADER | LVGF_GROUPID;
    wname = toWideString(name);
    g.pszHeader = wname;
    // for some reason the group ID and the index returned by LVM_INSERTGROUP are separate concepts... so we have to provide an ID.
    // (thanks to roxfan in irc.efnet.net/#winprog for confirming)
    g.iGroupId = id;
    n = SendMessage(listview, LVM_INSERTGROUP,
        (WPARAM) -1, (LPARAM) &g);
    if (n == (LRESULT) -1)
        panic("error adding list view group \"%s\"", name);
    free(wname);        // list views copy the name (thanks maztheman in irc.freenode.net/#winapi)
}

void buildUI(HWND mainwin)
{
#define CSTYLE (WS_CHILD | WS_VISIBLE)
#define CXSTYLE (0)
#define SETFONT(hwnd) SendMessage(hwnd, WM_SETFONT, (WPARAM) controlfont, (LPARAM) TRUE);

    listview = CreateWindowEx(CXSTYLE,
        WC_LISTVIEW, L"",
        LVS_ICON | WS_VSCROLL | CSTYLE,
        0, 0, 100, 100,
        mainwin, NULL, hInstance, NULL);
    if (listview == NULL)
        panic("error creating list view");

    int itemid = 0;

    // we need to have an item to be able to add a group
    LVITEM dummy;

    ZeroMemory(&dummy, sizeof (LVITEM));
    dummy.mask = LVIF_TEXT;
    dummy.pszText = L"dummy";
    dummy.iItem = itemid++;
    if (SendMessage(listview, LVM_INSERTITEM,
        0, (LPARAM) &dummy) == (LRESULT) -1)
        panic("error adding dummy item to list view");
    // the dummy item has index 0

    HIMAGELIST icons;

    icons = ImageList_Create(32, 32, ILC_COLOR32, 100, 100);
    if (icons == NULL)
        panic("error creating icon list for list view");
    if (SendMessage(listview, LVM_SETIMAGELIST,
        LVSIL_NORMAL, (LPARAM) icons) == (LRESULT) NULL)
;//     panic("error giving icon list to list view");

    if (SendMessage(listview, LVM_ENABLEGROUPVIEW,
        (WPARAM) TRUE, (LPARAM) NULL) == (LRESULT) -1)
        panic("error enabling groups in list view");

    DIR *dir;
    int groupid = 0;

    dir = opendir(dirname);
    if (dir == NULL)
        panic("error opening \"%s\": %s", dirname, strerror(errno));
    for (;;) {
        struct dirent *entry;
        char *filename;
        TCHAR *wfilename;

        errno = 0;
        entry = readdir(dir);
        if (entry == NULL) {
            if (errno != 0)
                panic("error reading \"%s\": %s", dirname, strerror(errno));
            break;      // otherwise, we're done
        }

        if (asprintf(&filename, "%s\\%s", dirname, entry->d_name) == -1)
            panic("error allocating combined filename %s\\%s: %s",
                dirname, entry->d_name, strerror(errno));
        wfilename = toWideString(filename);
        free(filename);

        UINT i, nIcons;

        addGroup(listview, entry->d_name, groupid);

        nIcons = (UINT) ExtractIcon(hInstance, wfilename, -1);
        // no need to check for no icons; nothing will happen
        for (i = 0; i < nIcons; i++) {
            HICON icon;
            int index;

            icon = ExtractIcon(hInstance, wfilename, i);
            if (icon == NULL || icon == (HICON) 1)      // NULL if no icons; 1 if cannot hold icons
                break;
            index = ImageList_AddIcon(icons, icon);
            if (index == -1)
                panic("error adding icon %u from %s to image list", i, entry->d_name);

            LVITEM item;

            ZeroMemory(&item, sizeof (LVITEM));
            item.mask = LVIF_IMAGE | LVIF_GROUPID | LVIF_TEXT;
            item.iImage = index;
            item.iGroupId = groupid;
            char *q;
            asprintf(&q, "%d", itemid);
            item.pszText = toWideString(q);
            free(q);
            item.iItem = itemid++;
            if (SendMessage(listview, LVM_INSERTITEM,
                (WPARAM) -1, (LPARAM) &item) == (LRESULT) -1)
                panic("error adding icon %u from %s to list view", i, entry->d_name);
        }
        free(wfilename);
        groupid++;
    }
    closedir(dir);

    // and we're done with the dummy item
    if (SendMessage(listview, LVM_DELETEITEM, 0, 0) == FALSE)
        panic("error removing dummy item from list view");
}

void firstShowWindow(HWND hwnd);

int main(int argc, char *argv[])
{
    HWND mainwin;
    MSG msg;

    init(argc, argv);

    mainwin = makeMainWindow();
    buildUI(mainwin);
    firstShowWindow(mainwin);

    for (;;) {
        BOOL gmret;

        gmret = GetMessage(&msg, NULL, 0, 0);
        if (gmret == -1)
            panic("error getting message");
        if (gmret == 0)
            break;
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}

DWORD iccFlags =
//  ICC_ANIMATE_CLASS |         // animation control
//  ICC_BAR_CLASSES |               // toolbar, statusbar, trackbar, tooltip
//  ICC_COOL_CLASSES |          // rebar
//  ICC_DATE_CLASSES |          // date and time picker
//  ICC_HOTKEY_CLASS |          // hot key
//  ICC_INTERNET_CLASSES |      // IP address entry field
//  ICC_LINK_CLASS |                // hyperlink
    ICC_LISTVIEW_CLASSES |          // list-view, header
//  ICC_NATIVEFNTCTL_CLASS |        // native font
//  ICC_PAGESCROLLER_CLASS |        // pager
//  ICC_PROGRESS_CLASS |            // progress bar
//  ICC_STANDARD_CLASSES |      // "one of the intrinsic User32 control classes"
//  ICC_TAB_CLASSES |               // tab, tooltip
//  ICC_TREEVIEW_CLASSES |      // tree-view, tooltip
//  ICC_UPDOWN_CLASS |          // up-down
//  ICC_USEREX_CLASSES |            // ComboBoxEx
//  ICC_WIN95_CLASSES |         // some of the above
    0;

void initwin(void)
{
    INITCOMMONCONTROLSEX icc;
    NONCLIENTMETRICS ncm;

    hInstance = GetModuleHandle(NULL);
    if (hInstance == NULL)
        panic("error getting hInstance");
    hDefaultIcon = LoadIcon(NULL, MAKEINTRESOURCE(IDI_APPLICATION));
    if (hDefaultIcon == NULL)
        panic("error getting default window class icon");
    hDefaultCursor = LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW));
    if (hDefaultCursor == NULL)
        panic("error getting default window cursor");
    icc.dwSize = sizeof (INITCOMMONCONTROLSEX);
    icc.dwICC = iccFlags;
    if (InitCommonControlsEx(&icc) == FALSE)
        panic("error initializing Common Controls");
    ncm.cbSize = sizeof (NONCLIENTMETRICS);
    if (SystemParametersInfo(SPI_GETNONCLIENTMETRICS,
        sizeof (NONCLIENTMETRICS), &ncm, 0) == 0)
        panic("error getting non-client metrics for getting control font");
    controlfont = CreateFontIndirect(&ncm.lfMessageFont);
    if (controlfont == NULL)
        panic("error getting control font");
}

void init(int argc, char *argv[])
{
    int usageExit = 1;
    char *opthelp[512];     // more than enough
    int i;

    for (i = 0; flags[i].name != 0; i++) {
        opthelp[i] = (char *) flags[i].flag;
        flags[i].flag = NULL;
    }

    for (;;) {
        int c;

        c = getopt_long_only(argc, argv, "", flags, NULL);
        if (c == -1)
            break;
        switch (c) {
        case 'h':       // -help
            usageExit = 0;
            goto usage;
        case '?':
            // getopt_long_only() should have printed something since we did not set opterr to 0
            goto usage;
        default:
            fprintf(stderr, "internal error: getopt_long_only() returned %d\n", c);
            exit(1);
        }
    }

    if (parseArgs(argc, argv) != TRUE)
        goto usage;

    initwin();
    return;

usage:
    fprintf(stderr, "usage: %s [options]", argv[0]);
    if (args != NULL && *args != '\0')
        fprintf(stderr, " %s", args);
    fprintf(stderr, "\n");
    for (i = 0; flags[i].name != 0; i++)
        fprintf(stderr, "\t-%s%s - %s\n",
            flags[i].name,
            (flags[i].has_arg == required_argument) ? " string" : "",
            opthelp[i]);
    exit(usageExit);
}

void panic(char *fmt, ...)
{
    char *msg;
    TCHAR *lerrmsg;
    char *fullmsg;
    va_list arg;
    DWORD lasterr;
    DWORD lerrsuccess;

    lasterr = GetLastError();
    va_start(arg, fmt);
    if (vasprintf(&msg, fmt, arg) == -1) {
        fprintf(stderr, "critical error: vasprintf() failed in panic() preparing panic message; fmt = \"%s\"\n", fmt);
        abort();
    }
    // according to http://msdn.microsoft.com/en-us/library/windows/desktop/ms680582%28v=vs.85%29.aspx
    lerrsuccess = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL, lasterr,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPTSTR) &lerrmsg, 0, NULL);
    if (lerrsuccess == 0) {
        fprintf(stderr, "critical error: FormatMessage() failed in panic() preparing GetLastError() string; panic message = \"%s\", last error in panic(): %ld, last error from FormatMessage(): %ld\n", msg, lasterr, GetLastError());
        abort();
    }
    // note to self: use %ws instead of %S (thanks jon_y in irc.oftc.net/#mingw-w64)
    if (asprintf(&fullmsg, "panic: %s\nlast error: %ws\n", msg, lerrmsg) == -1) {
        fprintf(stderr, "critical error: asprintf() failed in panic() preparing full report; panic message = \"%s\", last error message: \"%ws\"\n", msg, lerrmsg);
        abort();
    }
    fprintf(stderr, "%s\n", fullmsg);
    va_end(arg);
    exit(1);
}

void firstShowWindow(HWND hwnd)
{
    // we need to get nCmdShow
    int nCmdShow;
    STARTUPINFO si;

    nCmdShow = SW_SHOWDEFAULT;
    GetStartupInfo(&si);
    if ((si.dwFlags & STARTF_USESHOWWINDOW) != 0)
        nCmdShow = si.wShowWindow;
    ShowWindow(hwnd, nCmdShow);
    if (UpdateWindow(hwnd) == 0)
        panic("UpdateWindow(hwnd) failed in first show");
}

TCHAR *toWideString(char *what)
{
    TCHAR *buf;
    int n;
    size_t len;

    len = strlen(what);
    if (len == 0) {
        buf = (TCHAR *) malloc(sizeof (TCHAR));
        if (buf == NULL)
            goto mallocfail;
        buf[0] = L'\0';
    } else {
        n = MultiByteToWideChar(CP_UTF8, 0, what, -1, NULL, 0);
        if (n == 0)
            panic("error getting number of bytes to convert \"%s\" to UTF-16", what);
        buf = (TCHAR *) malloc((n + 1) * sizeof (TCHAR));
        if (buf == NULL)
            goto mallocfail;
        if (MultiByteToWideChar(CP_UTF8, 0, what, -1, buf, n) == 0)
            panic("erorr converting \"%s\" to UTF-16", what);
    }
    return buf;
mallocfail:
    panic("error allocating memory for UTF-16 version of \"%s\"", what);
}

更新

[2014年5月2日星期五20:00:48]我添加了组名的排序（未反映在上面的代码中），现在是第一种情况（！LVM_ENABLEGROUPVIEW＆amp;＆amp; LVM_DELETEITEM），最后一项再次出现......我开始认为某些事情没有被定义，但我不确定是什么

winapi：LVM_DELETEITEM以分组列表视图的不寻常方式运行

更新

0 个答案: