Cairo.WindowsHooksWrapper.NativeMethods.GetFileNameFromHandle C# (CSharp) Метод

        public static string GetFileNameFromHandle(IntPtr FileHandle)
        {
            string fileName = String.Empty;
            IntPtr fileMap = IntPtr.Zero, fileSizeHi = IntPtr.Zero;
            UInt32 fileSizeLo = 0;

            fileSizeLo = GetFileSize(FileHandle, fileSizeHi);

            if (fileSizeLo == 0)
            {
                // cannot map an 0 byte file
                return "Empty file.";
            }

            fileMap = CreateFileMapping(FileHandle, IntPtr.Zero, FileMapProtection.PageReadonly, 0, 1, null);

            if (fileMap != IntPtr.Zero)
            {
                IntPtr pMem = MapViewOfFile(fileMap, FileMapAccess.FileMapRead, 0, 0, 1);
                if (pMem != IntPtr.Zero)
                {
                    StringBuilder fn = new StringBuilder(250);
                    GetMappedFileName(System.Diagnostics.Process.GetCurrentProcess().Handle, pMem, fn, 250);
                    if (fn.Length > 0)
                    {
                        UnmapViewOfFile(pMem);
                        CloseHandle(FileHandle);
                        return fn.ToString();
                    }
                    else
                    {
                        UnmapViewOfFile(pMem);
                        CloseHandle(FileHandle);
                        return "Empty filename.";
                    }
                }
            }

            return "Empty filemap handle.";
        }