Question

void TestDirChanges(LPCWSTR path)
{
/*
FileName member of FILE_NOTIFY_INFORMATION has only one WCHAR according to definition. Most likely, this field will have more characters. 
So the expected size of one item is (sizeof(FILE_NOTIFY_INFORMATION) + MAX_PATH * sizeof(WCHAR)).
Prepare buffer for 256 items.
*/
char buf[256 * (sizeof(FILE_NOTIFY_INFORMATION) + MAX_PATH * sizeof(WCHAR))] = {0};
DWORD bytesReturned = 0;
BOOL result = FALSE;
FILE_NOTIFY_INFORMATION *fni = NULL;

HANDLE hDir = CreateFile(path,
    FILE_LIST_DIRECTORY | STANDARD_RIGHTS_READ,
    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
    NULL,
    OPEN_EXISTING,
    FILE_FLAG_BACKUP_SEMANTICS,
    NULL);

if (!hDir || hDir == INVALID_HANDLE_VALUE)
{
    wprintf(L"CreateFile failed\n");
    return;
}

while (1)
{
    result = ReadDirectoryChangesW(hDir,
        buf,
        sizeof(buf) / sizeof(*buf),
        TRUE, /* monitor the entire subtree */
        FILE_NOTIFY_CHANGE_FILE_NAME |
            FILE_NOTIFY_CHANGE_DIR_NAME |
            FILE_NOTIFY_CHANGE_ATTRIBUTES |
            FILE_NOTIFY_CHANGE_SIZE | 
            FILE_NOTIFY_CHANGE_LAST_WRITE | 
            FILE_NOTIFY_CHANGE_LAST_ACCESS |
            FILE_NOTIFY_CHANGE_CREATION |
            FILE_NOTIFY_CHANGE_SECURITY,
        &bytesReturned,
        NULL,
        NULL);

    if (result && bytesReturned)
    {
        wchar_t filename[MAX_PATH];
        wchar_t action[256];
        for (fni = (FILE_NOTIFY_INFORMATION*)buf; fni; )
        {
            switch (fni->Action)
            {
            case FILE_ACTION_ADDED:
                wcscpy_s(action, sizeof(action) / sizeof(*action), L"File added:");
                break;

            case FILE_ACTION_REMOVED:
                wcscpy_s(action, sizeof(action) / sizeof(*action), L"File removed:");
                break;

            case FILE_ACTION_MODIFIED:
                wcscpy_s(action, sizeof(action) / sizeof(*action), L"File modified:");
                break;

            case FILE_ACTION_RENAMED_OLD_NAME:
                wcscpy_s(action, sizeof(action) / sizeof(*action), L"File renamed, was:");
                break;

            case FILE_ACTION_RENAMED_NEW_NAME:
                wcscpy_s(action, sizeof(action) / sizeof(*action), L"File renamed, now is:");
                break;

            default:
                swprintf_s(action, sizeof(action) / sizeof(*action), L"Unkonwn action: %ld. File name is:", fni->Action);
            }

            if (fni->FileNameLength)
            {
                wcsncpy_s(filename, MAX_PATH, fni->FileName, fni->FileNameLength / 2);
                filename[fni->FileNameLength / 2] = 0;
                wprintf(L"%s '%s'\n", action, filename);
            }
            else
            {
                wprintf(L"%s <EMPTY>\n", action);
            }                

            if (fni->NextEntryOffset)
            {
                char *p = (char*)fni;
                fni = (FILE_NOTIFY_INFORMATION*)(p + fni->NextEntryOffset);
            }
            else
            {
                fni = NULL;
            }
        }
    }
    else
    {
        wprintf(L"ReadDirectoryChangesW failed\n");
    }
}

CloseHandle(hDir);
}

我的代码在WIN32控制台上运行良好但是当我在WIN32项目中使用它时，ReadDirectoryChangesW不起作用。它运行，我的编程停止工作。请帮帮我，谢谢，

Answer 1

看起来你正在阻止win32项目中的UI线程，应用程序似乎已冻结，它不会响应。启动一个工作线程并在工作线程中执行这些操作。

我认为最好使用SHChangeNotifyRegister之类的通知API，它可以让您知道目录是否发生任何更改，然后您可以读取目录而不是在while循环中执行此操作。应用程序unicode也是？您正在使用ReadDirectoryChangesW？

http://msdn.microsoft.com/en-us/library/windows/desktop/bb762120.aspx

WIND API项目中的ReadDirectoryChangesW错误？

1 个答案: