private static string BuildTijden(Moment[] momenten)
 {
   var builder = new StringBuilder();
   builder.AppendLine("<table>");
   foreach(var datum in momenten.Select(m => string.Format("<tr><th style=\"text-align: left;\">{0}</th><td>{1} - {2}</td></tr>", m.Datum, m.Begintijd, m.Eindtijd))){
     builder.AppendLine(datum);
   }
   builder.AppendLine("</table>");
   return builder.ToString();
 }