public string GroupBy { get; set; }

Public Property GroupBy As String
	Get
	Set

SphinxClient sphinxClient = new SphinxClient();
sphinxClient.SearchOptions.GroupBy = "last_update";
sphinxClient.SearchOptions.GroupByFunction = SphinxGroupByFunction.Day;

SphinxSearchResult searchResult = sphinxClient.Query("room", "sakila");

foreach (SphinxMatch match in searchResult.Matches)
{
    Console.WriteLine("DocumentId {0} Weight {1}", match.DocumentId, match.Weight);
}