asp.net Access分页类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DAL
{
    public class FastPageSql
    {
        private int allCount; //表中记录总数
        private bool isDesc; //排序方式
        private string primaryKey; //表的主键
        private string orderKey; //排序键
        private string selectFields; //要选择的字段
        private string queryCondition; //筛选条件
        private string tableName; //表名称
        private int perPageCount; //每页显示数
        private int pageIndex;  //显示页的索引
        private int totalIndex;     //总页数
        private int middleIndex; //中间页数;
        /// <summary>
        ///
        /// </summary>
        /// <param name="allcount">表中记录总数</param>
        /// <param name="isdesc">排序方式</param>
        /// <param name="primarykey">表的主键</param>
        /// <param name="orderkey">排序键</param>
        /// <param name="tablename">表名称</param>
        /// <param name="perpagecount">每页显示数</param>
        /// <param name="pageindex">显示页的索引</param>
        /// <param name="selectfields">要选择的字段</param>
        /// <param name="querycondition">筛选条件</param>
        public FastPageSql(int allcount, bool isdesc, string primarykey, string orderkey, string tablename, int perpagecount, int pageindex, string selectfields, string querycondition)
        {
            allCount = allcount;
            isDesc = isdesc;
            primaryKey = primarykey;
            orderKey = orderkey;
            selectFields = selectfields;
            queryCondition = querycondition;
            tableName = tablename;
            perPageCount = perpagecount;
            pageIndex = pageindex;
            totalIndex = getTotalIndex();
            middleIndex = (int)(totalIndex / 2);
        }
        private int getTotalIndex()
        {
            if (allCount % perPageCount > 0)
                return (int)(allCount / perPageCount) + 1;
            else
                return allCount / perPageCount;

        }
        public string GetFastPageSql()
        {
            string sql = "";
            if (pageIndex <= 1)
            {
                #region 第一页代码
                sql = "select top " + perPageCount + " " + selectFields + " from " + tableName + " " + ((queryCondition != "") ? "where " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + "";
                #endregion
            }
            else if (1 < pageIndex && pageIndex <= middleIndex)
            {
                #region 中间页之前
                if (primaryKey == orderKey)
                    sql = "select top " + perPageCount + " " + selectFields + " from " + tableName + " where " + primaryKey + "" + ((isDesc) ? "<" : ">") + "(select " + ((isDesc) ? "min" : "max") + "(" + primaryKey + ") from(select top " + perPageCount * (pageIndex - 1) + " " + primaryKey + " from " + tableName + " " + ((queryCondition != "") ? "where " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + " )) " + ((queryCondition != "") ? "and " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + "";
                else
                    sql = "select " + selectFields + " from (select top " + perPageCount + " " + selectFields + " from (select top " + perPageCount * pageIndex + " " + selectFields + " from " + tableName + " " + ((queryCondition != "") ? "where " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + ") order by " + orderKey + " " + ((isDesc) ? "asc" : "desc") + ") order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + "";
                #endregion

            }
            else if (middleIndex < pageIndex && pageIndex < totalIndex)
            {
                #region 中间页到最后页之间
                if (primaryKey == orderKey)
                    sql = "select " + selectFields + " from (select top " + perPageCount + " " + selectFields + " from " + tableName + " where " + primaryKey + "" + ((isDesc) ? ">" : "<") + "(select " + ((isDesc) ? "max" : "min") + "(" + primaryKey + ") from (select top " + (allCount - perPageCount * pageIndex) + " " + primaryKey + " from " + tableName + " " + ((queryCondition != "") ? "where " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "asc" : "desc") + " )) " + ((queryCondition != "") ? "and " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "asc" : "desc") + ") order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + "";
                else
                    sql = "select top " + perPageCount + " " + selectFields + " from (select top " + (allCount - (pageIndex - 1) * perPageCount) + " " + selectFields + " from " + tableName + " " + ((queryCondition != "") ? "where " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "asc" : "desc") + ") order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + "";

                #endregion


            }
            else if (pageIndex >= totalIndex)
            {
                #region 最后页
                sql = "select " + selectFields + " from (select top " + (allCount - (totalIndex - 1) * perPageCount) + " " + selectFields + " from " + tableName + " " + ((queryCondition != "") ? "where " + queryCondition + "" : "") + " order by " + orderKey + " " + ((isDesc) ? "asc" : "desc") + ") order by " + orderKey + " " + ((isDesc) ? "desc" : "asc") + "";
                #endregion

            }
            return sql;
        }

    }
}