System.IO.DirectoryInfo.CreateSubdirectoryHelper C# (CSharp) Method

        private DirectoryInfo CreateSubdirectoryHelper(String path)
        {
            Debug.Assert(path != null);

            PathHelpers.ThrowIfEmptyOrRootedPath(path);

            String newDirs = Path.Combine(FullPath, path);
            String fullPath = Path.GetFullPath(newDirs);

            if (0 != String.Compare(FullPath, 0, fullPath, 0, FullPath.Length, PathInternal.StringComparison))
            {
                throw new ArgumentException(SR.Format(SR.Argument_InvalidSubPath, path, DisplayPath), nameof(path));
            }

            FileSystem.Current.CreateDirectory(fullPath);

            // Check for read permission to directory we hand back by calling this constructor.
            return new DirectoryInfo(fullPath);
        }