System.IO.Win32FileSystem.CopyFile C# (CSharp) Méthode

        public override void CopyFile(string sourceFullPath, string destFullPath, bool overwrite)
        {
            Interop.Kernel32.SECURITY_ATTRIBUTES secAttrs = default(Interop.Kernel32.SECURITY_ATTRIBUTES);
            int errorCode = Interop.Kernel32.CopyFile(sourceFullPath, destFullPath, !overwrite);

            if (errorCode != Interop.Errors.ERROR_SUCCESS)
            {
                string fileName = destFullPath;

                if (errorCode != Interop.Errors.ERROR_FILE_EXISTS)
                {
                    // For a number of error codes (sharing violation, path 
                    // not found, etc) we don't know if the problem was with
                    // the source or dest file.  Try reading the source file.
                    using (SafeFileHandle handle = Interop.Kernel32.UnsafeCreateFile(sourceFullPath, GENERIC_READ, FileShare.Read, ref secAttrs, FileMode.Open, 0, IntPtr.Zero))
                    {
                        if (handle.IsInvalid)
                            fileName = sourceFullPath;
                    }

                    if (errorCode == Interop.Errors.ERROR_ACCESS_DENIED)
                    {
                        if (DirectoryExists(destFullPath))
                            throw new IOException(SR.Format(SR.Arg_FileIsDirectory_Name, destFullPath), Interop.Errors.ERROR_ACCESS_DENIED);
                    }
                }

                throw Win32Marshal.GetExceptionForWin32Error(errorCode, fileName);
            }
        }