public override async Task<PagerList<NewsContentDto>> PagerQueryAsync(NewsContentQuery parameter)

        {

            FilterDefinitionBuilder<NewsContentDto> builder = Builders<NewsContentDto>.Filter;

            string p = parameter.Keyword == null? $".*{Regex.Escape("")}.*": $".*{Regex.Escape(parameter.Keyword)}.*";

            FilterDefinition <NewsContentDto> filter2 = builder.Regex("title", new BsonRegularExpression(new Regex(p, RegexOptions.IgnoreCase)));

            //var filter1 = Builders<T>.Filter.Regex("title", new BsonRegularExpression(new Regex(".*" + Regex.Escape("英超") + ".*", RegexOptions.IgnoreCase)));

            //var filter1 = Filter.Regex(x => x.EnglishName, new MongoDB.Bson.BsonRegularExpression(parameter.Keyword, "i"));

            //BsonDocument filter = new BsonDocument {{"title", $"/{parameter.Keyword}/" } };

            //if(parameter.classifyId>0) filter.Add("classifyId", parameter.classifyId);

            var query = new QueryMongoParameter<NewsContentDto>(parameter, "news_content", filter2);

            var ret = await MongoContext.PagerQueryAsync(query);

            return ret;

        }

        public async Task<PagerList<T>> PagerQueryAsync<T>(QueryMongoParameter<T> query)

        {

            var skip = (query.Page - ) * query.PageSize;

            var collection = _database.GetCollection<T>(query.CollectName);

            var data = await collection.Find(query.Filter).Sort(query.Sort).Project(query.Projection).Skip(skip).Limit(query.PageSize).ToListAsync();

            var total = await collection.CountAsync(query.Filter);

            var ret = new List<T>();

            data.ForEach(d =>

            {

                string s = d.ToString().Replace("\"_id\"", "\"id\"");

                ret.Add(Helpers.Json.ToObject<T>(s));

            });

            return new PagerList<T>(query.Page, query.PageSize, (int)total, ret);

        }

    public class PageMongoParameter : ParameterBase

    {

        public BsonDocument Sort { get; }

        public BsonDocument Skip { get; }

        public BsonDocument Limit { get;}

        public BsonDocument Filter2 { get; }

        public BsonDocument[] Pipeline { get; set; }

        public PageMongoParameter(PageRequest req, string collectName, BsonDocument filter=null,BsonDocument sort=null, BsonDocument filter2 = null)

        {

            CollectName = collectName;

            Page = req.pageindex;

            PageSize = req.pagesize;

            Limit = new BsonDocument { { "$limit", PageSize } };

            Skip = new BsonDocument { { "$skip", (Page-)*PageSize} };

            if (sort == null)

            {

                if (!string.IsNullOrEmpty(req.order)) Sort = new BsonDocument { { "$sort", new BsonDocument { { req.order,  } } } };

            }

            else

            {

                Sort = sort;

            }

            if (filter != null && filter2==null)

            {

                var dom = filter.GetElement();

                Filter2 = BsonDocument.Parse(dom.Value.ToJson());

            }

            Filter2 = Filter2 ?? new BsonDocument();

            if (filter == null && Sort == null)

                Pipeline = new[] {Skip, Limit};

            else

            {

                if(filter!=null && Sort != null)

                    Pipeline = new[] { filter,Skip, Limit,Sort };

                else

                    Pipeline = filter == null ? new[] {Skip, Limit, Sort} : new[] { filter,Skip, Limit};

            }

        }

    }