Catel.IO.Path.GetRelativePath C# (CSharp) Метод

        public static string GetRelativePath(string fullPath, string basePath = null)
        {
            Argument.IsNotNullOrWhitespace("fullPath", fullPath);

#if !NETFX_CORE && !PCL
            if (string.IsNullOrEmpty(basePath))
            {
                basePath = Environment.CurrentDirectory;
            }
#endif

            fullPath = RemoveTrailingSlashes(fullPath.ToLower());
            basePath = RemoveTrailingSlashes(basePath.ToLower());

            // Check if the base path is really the full path (not just a subpath, for example "C:\MyTes" in "C:\MyTest")
            string fullPathWithTrailingBackslash = AppendTrailingSlash(fullPath);
            string basePathWithTrailingBackslash = AppendTrailingSlash(basePath);

            if (fullPathWithTrailingBackslash.IndexOf(basePathWithTrailingBackslash) > -1)
            {
                string result = fullPath.Replace(basePath, string.Empty);
                if (result.StartsWith("\\"))
                {
                    result = result.Remove(0, 1);
                }

                return result;
            }

            string backDirs = string.Empty;
            string partialPath = basePath;
            int index = partialPath.LastIndexOf("\\");
            while (index > 0)
            {
                partialPath = AppendTrailingSlash(partialPath.Substring(0, index));
                backDirs = backDirs + "..\\";

                if (fullPathWithTrailingBackslash.IndexOf(partialPath) > -1)
                {
                    partialPath = RemoveTrailingSlashes(partialPath);
                    fullPath = RemoveTrailingSlashes(fullPath);

                    if (fullPath == partialPath)
                    {
                        // *** Full Directory match and need to replace it all
                        return fullPath.Replace(partialPath, backDirs.Substring(0, backDirs.Length - 1));
                    }
                    else
                    {
                        // *** We're dealing with a file or a start path
                        return fullPath.Replace(partialPath + (fullPath == partialPath ? string.Empty : "\\"), backDirs);
                    }
                }

                partialPath = RemoveTrailingSlashes(partialPath);
                index = partialPath.LastIndexOf("\\", partialPath.Length - 1);
            }

            return fullPath;
        }