private IEnumerable<Model.SearchSum> DoSelect()
        {
            DataTable dt = SqlHelper.ExecuteDataTable(@"
select top 5 Keyword,count(*) as searchcount  from keywords 
where datediff(day,searchdatetime,getdate())<7
group by Keyword 
order by count(*) desc ");
            List<Model.SearchSum> list = new List<Model.SearchSum>();
            if (dt!=null&&dt.Rows!=null&&dt.Rows.Count>0)
            {
                foreach (DataRow row in dt.Rows)
                {
                    Model.SearchSum oneModel=new Model.SearchSum ();
                    oneModel.Keyword = Convert.ToString(row["keyword"]);
                    oneModel.SearchCount = Convert.ToInt32(row["SearchCount"]);
                    list.Add(oneModel);
                }
            }
            return list;
        }
        public IEnumerable<Model.SearchSum> GetSuggestion(string kw)
        {
            DataTable dt = SqlHelper.ExecuteDataTable(@"select top 5 Keyword,count(*) as searchcount  from keywords 
where datediff(day,searchdatetime,getdate())<7
and keyword like @keyword
group by Keyword 
order by count(*) desc",new SqlParameter("@keyword","%"+kw+"%"));
            List<Model.SearchSum> list = new List<Model.SearchSum>();
            if (dt != null && dt.Rows != null && dt.Rows.Count > 0)
            {
                foreach (DataRow row in dt.Rows)
                {
                    Model.SearchSum oneModel = new Model.SearchSum();
                    oneModel.Keyword = Convert.ToString(row["keyword"]);
                    oneModel.SearchCount = Convert.ToInt32(row["SearchCount"]);
                    list.Add(oneModel);
                }
            }
            return list;
        }