private static void getMetadataFromAttributes(IShellFolder dir, string fileName, ref IList <string> authors, ref IList <string> keywords)
{
var shellFile = dir.GetFile(fileName);
string authorsValue = shellFile.GetAuthors();
string keywordsValue = shellFile.GetKeywords();
add(ref authors, authorsValue?.Split(';').Select(_ => _.Trim()).ToArray());
add(ref keywords, keywordsValue?.Split(';').Select(_ => _.Trim()).ToArray());
}