private static string joinParams(Dictionary <string, string> pars) { var result = new List <Tuple <string, string> >(); foreach (var paramName in pars.Keys) { var paramContent = pars[paramName]; var values = paramContent.Split(','); foreach (var value in values) { result.Add(new Tuple <string, string>(paramName, value)); } } return(QueryParam.Join(result)); }