C# FindFile FindFirstFile FindNextFile IEnumerable

FindFile.cs

    /// <summary>
    /// var ff = new FindFile(); ff.Path = @"c:\"; (var _fd in ff) {var filepath = _fd.cFileName;}
    /// </summary>
    public class FindFile : IEnumerable<WIN32_FIND_DATA>
    {
        public string Path { get; set; }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return new Enumerator(Path);
        }

        IEnumerator<WIN32_FIND_DATA> IEnumerable<WIN32_FIND_DATA>.GetEnumerator()
        {
            return new Enumerator(Path);
        }

        [Serializable]
        public struct Enumerator : IEnumerator<WIN32_FIND_DATA>
        {
            private WIN32_FIND_DATA _finddata;
            private readonly string _path;
            private Win32Api.SafeFindHandle _handle;

            public WIN32_FIND_DATA Current { get; private set; }

            object IEnumerator.Current
            {
                get { return Current; }
            }

            internal Enumerator(string path)
            {
                _path = path;
                _finddata = default(WIN32_FIND_DATA);
                Current = default(WIN32_FIND_DATA);
                _handle = null;
            }

            public void Dispose()
            {
            }

            public bool MoveNext()
            {
                if (_handle == null)
                {
                    _handle = Win32Api.FindFirstFile(_path + @"\*", out _finddata);

                    if (_handle.IsInvalid)
                        return false;

                    Current = _finddata;
                    return true;
                }
                if (!Win32Api.FindNextFile(_handle, out _finddata))
                    return false;

                Current = _finddata;
                return true;
            }

            void IEnumerator.Reset()
            {
                Current = default(WIN32_FIND_DATA);
                _handle = null;
                _finddata = default(WIN32_FIND_DATA);
            }
        }
    }

[Serializable]
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    [BestFitMapping(false)]
    public struct WIN32_FIND_DATA
    {
        public FileAttributes dwFileAttributes;
        public FILETIME ftCreationTime;
        public FILETIME ftLastAccessTime;
        public FILETIME ftLastWriteTime;
        public uint nFileSizeHigh;
        public uint nFileSizeLow;
        public uint dwReserved0;
        public uint dwReserved1;

        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
        public string cFileName;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 14)]
        public string cAlternate;
    }

[SecurityCritical]
        public class SafeFindHandle : SafeHandleZeroOrMinusOneIsInvalid
        {
            [SecurityCritical]
            internal SafeFindHandle()
                : base(true)
            {
            }

            [DllImport("kernel32.dll", SetLastError = true)]
            private static extern bool FindClose(IntPtr hFindFile);

            [SecurityCritical]
            protected override bool ReleaseHandle()
            {
                return FindClose(handle);
            }
        }

[DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern SafeFindHandle FindFirstFile(
            string lpFileName,
            out WIN32_FIND_DATA lpFindFileData);

        [DllImport("kernel32", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern bool FindNextFile(
            SafeFindHandle hFindFile,
            out WIN32_FIND_DATA lpFindFileData);