Question

我试图实现一个方法，它将创建我需要的所有标准并执行并返回数据。这是方法。

        /// <summary>
        /// Fetches a paged collection of entities from the database. Use this method when you only need a certain amount of information.
        /// </summary>
        /// <typeparam name="TType"></typeparam>
        /// <param name="pred"></param>
        /// <param name="pageNumber"></param>
        /// <param name="pageSize"></param>
        /// <param name="totalRecords"></param>
        /// <returns></returns>
        public IEnumerable<TType> FetchPagedCollection<TType>(System.Linq.Expressions.Expression<Func<TType, bool>> pred, int pageNumber, int pageSize, out int totalRecords) where TType : class
        {
            var multiCriteria = this._session.CreateMultiCriteria();

            ICriteria dataCriteria = this._session.CreateCriteria<TType>().Add(this.HandleBinaryExpression<TType>(pred));
            ICriteria countCriteria = CriteriaTransformer.TransformToRowCount(dataCriteria);//Changed this from Clone since it's what I really want...

            dataCriteria.SetMaxResults(pageSize);
            dataCriteria.SetFirstResult((pageNumber - 1) * pageSize);

            //countCriteria.SetProjection(Projections.RowCount());

            multiCriteria.Add<TType>(countCriteria);
            multiCriteria.Add<TType>(dataCriteria);

            IList result = multiCriteria.List(); <--Throws exception here.
            IEnumerable<TType> data = (IEnumerable<TType>)result[0];
            IList counts = (IList)result[1];
            totalRecords = (int)counts[0];

            if (this._ownsTransaction)
                this._transaction.Commit();

            return data;
        }

异常是有道理的，但我不确定如何解决它。该异常表明无法执行计数查询，因为返回值“0”不是类型为FavoriteWorker“

这是实际的异常文本：

{"Error executing multi criteria : 
[SELECT count(*) as y0_ FROM FavoriteWorkers this_ WHERE this_.UserID = ?p0;\r\n
SELECT this_.FavoriteWorkerID as Favorite1_0_0_, this_.UserID as UserID0_0_ 
FROM FavoriteWorkers this_ WHERE this_.UserID = ?p1 limit ?p2;]"}

InnerException Text

{"The value \"0\" is not of type \"FavoriteWorkerEntity\" 
and cannot be used in this generic collection.\r\nParameter name: value"}

有人有任何想法吗？

创建的查询类似于此SO答案：https://stackoverflow.com/a/433210/385565

NHibernate - MultiCriteria在尝试执行分页查询时抛出异常

0 个答案: