C# Rafy.PagingInfo类代码示例

 /// <summary>
 /// 在 sqlce 下，不支持 rowNumber 方案，但是支持 not in 方案。
 /// 鉴于实现 not in 方案比较耗时，所以暂时决定使用 IDataReader 分页完成。
 /// 
 /// not in 分页，参见以下 Sql：
 /// select top 10 [AuditItem].* from 
 /// [AuditItem] where 
 /// [AuditItem].id not in
 /// (
 ///     select top 100 [AuditItem].id from [AuditItem] order by LogTime desc
 /// )
 /// order by LogTime desc
 /// </summary>
 protected override PagingLocation GetPagingLocation(PagingInfo pagingInfo)
 {
     if (!PagingInfo.IsNullOrEmpty(pagingInfo) && pagingInfo.PageNumber == 1 && !pagingInfo.IsNeedCount)
     {
         return PagingLocation.Database;
     }
     return PagingLocation.Memory;
 }

        protected override sealed EntityList DoGetAll(PagingInfo paging, EagerLoadOptions eagerLoad)
        {
            if (!PagingInfo.IsNullOrEmpty(paging)) { throw new NotSupportedException(); }

            DataProvider.EnsureStore();
            var items = DataProvider._memoryRows.Values.Select(v => DataProvider.FromRow(v));
            var list = this.CreateList(items, false);
            TreeHelper.MarkTreeFullLoaded(list);

            return list;
        }

 public new OtherStorageInBillList GetByParentIdList(object[] parentIdList, PagingInfo paging = null, EagerLoadOptions eagerLoad = null)
 {
     return base.GetByParentIdList(parentIdList, paging, eagerLoad) as OtherStorageInBillList;
 }

 public new ChapterList GetAll(PagingInfo paging= null, EagerLoadOptions eagerLoad = null)
 {
     return base.GetAll(paging, eagerLoad) as ChapterList;
 }

 public new OperationACList GetAll(PagingInfo paging= null, EagerLoadOptions eagerLoad = null)
 {
     return base.GetAll(paging, eagerLoad) as OperationACList;
 }

        /// <summary>
        /// 访问 sql 语法树中的每一个结点，并生成相应的 Sql 语句。
        /// </summary>
        /// <param name="tree">The tree.</param>
        /// <param name="pagingInfo">The paging information.</param>
        public void Generate(SqlSelect tree, PagingInfo pagingInfo = null)
        {
            ISqlSelect res = tree;
            if (!PagingInfo.IsNullOrEmpty(pagingInfo))
            {
                res = ModifyToPagingTree(tree, pagingInfo);
            }

            base.Visit(res);
        }

 public new ProductAttachementList GetAll(PagingInfo paging= null, EagerLoadOptions eagerLoad = null)
 {
     return base.GetAll(paging, eagerLoad) as ProductAttachementList;
 }

 public new MonthPlanList GetAll(PagingInfo paging= null, EagerLoadOptions eagerLoad = null)
 {
     return base.GetAll(paging, eagerLoad) as MonthPlanList;
 }

 public new DevLanguageItemList GetAll(PagingInfo paging= null, EagerLoadOptions eagerLoad = null)
 {
     return base.GetAll(paging, eagerLoad) as DevLanguageItemList;
 }

 /// <summary>
 /// 在内存中对 IDataReader 进行读取，并以树的方式进行节点的加载。
 /// </summary>
 /// <param name="reader">表格类数据。</param>
 /// <param name="readType">是否索引还是名称去读取 IDataReader。</param>
 /// <param name="list">需要把读取的实体中的第一级的节点，加入到这个列表中。</param>
 /// <param name="markTreeFullLoaded">如果某次查询结果是一棵完整的子树，那么必须设置此参数为 true ，才可以把整个树标记为完整加载。</param>
 /// <param name="pagingInfo">对根节点进行分页的信息。</param>
 private void FillTreeIntoList(
     IDataReader reader, ReadDataType readType, IList<Entity> list,
     bool markTreeFullLoaded, PagingInfo pagingInfo)
 {
     var entities = this.ReadToEntity(reader, readType);
     if (PagingInfo.IsNullOrEmpty(pagingInfo))
     {
         TreeHelper.LoadTreeData(list, entities, _repository.TreeIndexOption);
     }
     else
     {
         //在内存中分页。
         var tempList =new List<Entity>();
         TreeHelper.LoadTreeData(tempList, entities, _repository.TreeIndexOption);
         var paged = tempList.JumpToPage(pagingInfo);
         foreach (var item in paged) { list.Add(item); }
     }
     if (markTreeFullLoaded)
     {
         TreeHelper.MarkTreeFullLoaded(list);
     }
 }

 /// <summary>
 /// 判断指定的分页操作，支持在哪个层面进行分页。
 /// </summary>
 /// <param name="pagingInfo">The paging information.</param>
 /// <returns></returns>
 protected abstract PagingLocation GetPagingLocation(PagingInfo pagingInfo);

        /// <summary>
        /// 在内存中对 IDataReader 进行读取。
        /// 注意！！！
        /// 此方法中会释放 Reader。外层不能再用 Using。
        /// </summary>
        /// <param name="reader">表格类数据。</param>
        /// <param name="readType">是否索引还是名称去读取 IDataReader。</param>
        /// <param name="list">需要把读取的实体，加入到这个列表中。</param>
        /// <param name="fetchingFirst">是否只读取一条数据即返回。</param>
        /// <param name="pagingInfo">如果不是只取一行数据，则这个参数表示列表内存分页的信息。</param>
        /// <param name="markTreeFullLoaded">如果某次查询结果是一棵完整的子树，那么必须设置此参数为 true ，才可以把整个树标记为完整加载。</param>
        protected void FillDataIntoList(
            IDataReader reader, ReadDataType readType,
            IList<Entity> list, bool fetchingFirst, PagingInfo pagingInfo, bool markTreeFullLoaded
            )
        {
            if (_repository.SupportTree)
            {
                this.FillTreeIntoList(reader, readType, list, markTreeFullLoaded, pagingInfo);
                return;
            }

            //如果正在分页，而且支持数据库层面的分页，则不使用内存分页。
            if (!PagingInfo.IsNullOrEmpty(pagingInfo) && this.GetPagingLocation(pagingInfo) == PagingLocation.Database)
            {
                pagingInfo = null;
            }

            var readByIndex = readType == ReadDataType.ByIndex;
            Action<IDataReader> rowReader = dr =>
            {
                var entity = readByIndex ? this.CreateByIndex(dr) : this.CreateByName(dr);
                list.Add(entity);
            };
            if (fetchingFirst)
            {
                if (reader.Read())
                {
                    rowReader(reader);
                }
            }
            else
            {
                PagingHelper.MemoryPaging(reader, rowReader, pagingInfo);
            }
        }

        /// <summary>
        /// 如果需要统计，则生成统计语句进行查询。
        /// </summary>
        /// <param name="dba"></param>
        /// <param name="pagingInfo"></param>
        /// <param name="parts"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        private static void QueryTotalCountIf(IDbAccesser dba, PagingInfo pagingInfo, PagingSqlParts parts, object[] parameters)
        {
            if (pagingInfo.IsNeedCount)
            {
                var pagingCountSql = "SELECT COUNT(0) " + parts.FromWhere;

                //查询值。（由于所有参数都不会在 OrderBy、Select 语句中，所以把所有参数都传入。
                var value = dba.QueryValue(pagingCountSql, parameters);
                pagingInfo.TotalCount = Convert.ToInt32(value);
            }
        }

 /// <summary>
 /// SqlServer 、 Oracle 都支持在数据库层面进行分页。
 /// </summary>
 protected override PagingLocation GetPagingLocation(PagingInfo pagingInfo)
 {
     //虽然本类默认使用数据库分页，但是它的子类可以重写本方法来使用内存分页。
     //所以本类中的所有方法，在重新实现时，都会分辨这两种情况。
     return PagingLocation.Database;
 }

        protected virtual void CreatePagingSql(ref PagingSqlParts parts, PagingInfo pagingInfo)
        {
            /*********************** 代码块解释 *********************************
             *
             * 注意，这个方法只支持不太复杂 SQL 的转换。
             *
             * 源格式：
             * select ...... from ...... order by xxxx asc, yyyy desc
             * 不限于以上格式，只要满足没有复杂的嵌套查询，最外层是一个 Select 和 From 语句即可。
             *
             * 目标格式：
             * select * from (select ......, row_number() over(order by xxxx asc, yyyy desc) _rowNumber from ......) x where x._rowNumber<10 and x._rowNumber>5;
            **********************************************************************/

            var startRow = pagingInfo.PageSize * (pagingInfo.PageNumber - 1) + 1;
            var endRow = startRow + pagingInfo.PageSize - 1;

            var sql = new StringBuilder("SELECT * FROM (");

            //在 Select 和 From 之间插入：
            //,row_number() over(order by UPDDATETIME desc) rn
            sql.AppendLine().Append(parts.Select)
                .Append(", row_number() over(")
                .Append(parts.OrderBy);
            //query.AppendSqlOrder(res, this);
            sql.Append(") dataRowNumber ").Append(parts.FromWhere)
                .Append(") x").AppendLine()
                .Append("WHERE x.dataRowNumber >= ").Append(startRow)
                .Append(" AND x.dataRowNumber <= ").Append(endRow);

            parts.PagingSql = sql.ToString();
        }