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

        public static Uri ResolvePartUri(Uri sourcePartUri, Uri targetUri)
        {
            Check.SourcePartUri(sourcePartUri);
            Check.TargetUri(targetUri);

            Check.PartUriIsValid(sourcePartUri);
             // commented out because on Android they are absolute file:///
            //   if (targetUri.IsAbsoluteUri)
             //       throw new ArgumentException("targetUri", "Absolute URIs are not supported");

            Uri uri = new Uri("http://fake.com");
            uri = new Uri(uri, sourcePartUri);
            uri = new Uri(uri, targetUri);

            // Trim out 'http://fake.com'
            return new Uri(uri.OriginalString.Substring(15), UriKind.Relative);
        }

        ParsePages()
        {
            Stream stream = _metroPart.GetStream(FileMode.Open);

            //
            // If the stream is empty there are no pages to parse
            //
            if (stream.Length > 0)
            {
                XmlTextReader reader = new XmlTextReader(stream);

                while (reader.Read())
                {
                    if (reader.NodeType == XmlNodeType.Element && reader.Name == XpsS0Markup.PageContent)
                    {
                        string attribute = reader.GetAttribute(XmlTags.Source);
                        if (attribute != null)
                        {
                            Uri relativeUri = new Uri(attribute, UriKind.Relative);
                            AddPageToCache(PackUriHelper.ResolvePartUri(Uri, relativeUri));
                        }
                    }
                }
            }
        }