Question

I am using a library that recursively scans really fast the files and directories of a folder. The output is a List<WIN32_FIND_DATAW> . Click here to see the contents of the stuct.

I managed to convert FILETIME to DateTime with the following extension method:

public static DateTime convertToDateTime(this System.Runtime.InteropServices.ComTypes.FILETIME time)
{
    ulong high = (ulong)time.dwHighDateTime;
    int low = time.dwLowDateTime;
    uint uLow = (uint)low;
    high = high << 32;
    return DateTime.FromFileTime((long)(high | (ulong)uLow));
}

and I get the file size as:

  (UInt64)((nFileSizeHigh * (2 ^ 32)) + nFileSizeLow);

I find those methods online don’t recall where.

Anyways the library contains a method that requires a list of WIN32_FIND_DATA. I want to call that method but I don’t know how to create a WIN32_FIND_DATA object

Here is a random WIN32_FIND_DATA object created when I iterated through my C:\ Drive

How could I construct the same object? I don’t know how to get the cAlternateName although I don’t think I need that. I don’t know how to go back and convert a DateTime to FILETIME. Lastly I don’t know how to convert a file size into nFileSizeHigh and nFileSizeLow.

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the library used this methods in order to constuct the WIN32_FIND_DATAW objects:

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
        public static extern IntPtr FindFirstFileW(string lpFileName, out WIN32_FIND_DATAW lpFindFileData);

        [DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
        public static extern bool FindNextFile(IntPtr hFindFile, out WIN32_FIND_DATAW lpFindFileData);

        [DllImport("kernel32.dll")]
        public static extern bool FindClose(IntPtr hFindFile); 

Maybe there exists a public static extern bool FindFile(IntPtr hFindFile, out WIN32_FIND_DATAW lpFindFileData); method. so that I can construct the WIN32_FIND_DATAW objects that I need.

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Edit

In short I want to construct a WIN32_FIND_DATAW object by having the full path of a file

Answer 1

Here is the declaration of necessary structures.

public struct FILETIME
{
     public UInt32 dwLowDateTime;
     public UInt32 dwHighDateTime;
}

public unsafe struct WIN32_FIND_DATAW
{
    public UInt32 dwFileAttributes;
    public FILETIME ftCreationTime;
    public FILETIME ftLastAccessTime;
    public FILETIME ftLastWriteTime;
    public UInt32 nFileSizeHigh;
    public UInt32 nFileSizeLow;
    public UInt32 dwReserved0;
    public UInt32 dwReserved1;
    public fixed Char cFileName[256];
    public fixed Char cAlternateFileName[14];
}

You can construct and initialize such object as usual structure in C#.

Update:
The 64-bit integer stored in FILETIME structure represents the number of 100-nanosecond intervals since January 1, 1601 (UTC). In .NET DateTime.Ticks represents the number of 100-nanosecond intervals that have elapsed since 12:00:00 midnight, January 1, 0001. So, to convert DateTime to FILETIME you just need to subtract 1600 years from DateTime and write number of ticks as pair of unsigned 32-bit integers. Or you can just call DateTime.ToFileTimeUtc():

FILETIME fileTime = new FILETIME();
Int64 ticks = DateTime.Now.ToFileTimeUtc();
fileTime.dwLowDateTime = (UInt32)ticks;
fileTime.dwHighDateTime = (UInt32)(ticks >> 32);