MongoDB.Driver.Builders.SortByBuilder.Ascending C# (CSharp) Method

        public SortByBuilder Ascending(params string[] keys)
        {
            foreach (var key in keys)
            {
                _document.Add(key, 1);
            }
            return this;
        }

 /// <summary>
 ///     获得排序
 /// </summary>
 /// <returns></returns>
 public static SortByBuilder GetSort(List<DataFilter.QueryFieldItem> FieldItemLst)
 {
     var sort = new SortByBuilder();
     var ascendingList = new List<String>();
     var descendingList = new List<String>();
     //_id将以文字的形式排序，所以不要排序_id!!
     foreach (DataFilter.QueryFieldItem item in FieldItemLst)
     {
         switch (item.sortType)
         {
             case DataFilter.SortType.NoSort:
                 break;
             case DataFilter.SortType.Ascending:
                 ascendingList.Add(item.ColName);
                 break;
             case DataFilter.SortType.Descending:
                 descendingList.Add(item.ColName);
                 break;
             default:
                 break;
         }
     }
     sort.Ascending(ascendingList.ToArray());
     sort.Descending(descendingList.ToArray());
     return sort;
 }