System.IO.Packaging.PackUriHelper.GetRelativeUri C# (CSharp) Method

        public static Uri GetRelativeUri(Uri sourcePartUri, Uri targetPartUri)
        {
            Check.SourcePartUri(sourcePartUri);
            Check.TargetPartUri(targetPartUri);

            Uri uri = new Uri("http://fake.com");
            Uri a = new Uri(uri, sourcePartUri.OriginalString);
            Uri b = new Uri(uri, targetPartUri.OriginalString);

            return a.MakeRelativeUri(b);
        }