access下的分页方案（仿sql存储过程）

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Data.OleDb;
using System.Web;

/// <summary>
/// 名称：access下的分页方案（仿sql存储过程）
/// 作者：cncxz(虫虫)
/// blog：http://cncxz.cnblogs.com/
/// </summary>
public class AccessPager
{
protected string m_ConnString;
protected OleDbConnection m_Conn;

public AccessPager(string connString)
{
m_Conn = new OleDbConnection(connString);
}

/// <summary>
/// 打开连接
/// </summary>
public void ConnOpen()
{
if (m_Conn.State != ConnectionState.Open)
m_Conn.Open();
}

/// <summary>
/// 关闭连接
/// </summary>
public void ConnClose()
{
if (m_Conn.State != ConnectionState.Closed)
m_Conn.Close();
}

private string recordID(string query, int passCount)
{
OleDbCommand cmd = new OleDbCommand(query, m_Conn);
string result = string.Empty;
using (IDataReader dr = cmd.ExecuteReader())
{
while (dr.Read())
{
if (passCount < 1)
{
result += "," + dr.GetInt32(0);
}
passCount--;
}
}
return result.Substring(1);
}

/// <summary>
/// 获取当前页应该显示的记录，注意：查询中必须包含名为ID的自动编号列，若不符合你的要求，就修改一下源码吧 :)
/// </summary>
/// <param name="pageIndex">当前页码</param>
/// <param name="pageSize">分页容量</param>
/// <param name="showString">显示的字段</param>
/// <param name="queryString">查询字符串，支持联合查询</param>
/// <param name="whereString">查询条件，若有条件限制则必须以where 开头</param>
/// <param name="orderString">排序规则</param>
/// <param name="pageCount">传出参数：总页数统计</param>
/// <param name="recordCount">传出参数：总记录统计</param>
/// <returns>装载记录的DataTable</returns>
public DataTable ExecutePager(int pageIndex, int pageSize, string showString, string queryString, string whereString, string orderString, out int pageCount, out int recordCount)
{
if (pageIndex < 1) pageIndex = 1;
if (pageSize < 1) pageSize = 10;
if (string.IsNullOrEmpty(showString)) showString = "*";
if (string.IsNullOrEmpty(orderString)) orderString = "ID desc";
ConnOpen();
string myVw = string.Format(" ( {0} ) tempVw ", queryString);
OleDbCommand cmdCount = new OleDbCommand(string.Format(" select count(0) as recordCount from {0} {1}", myVw, whereString), m_Conn);

recordCount = Convert.ToInt32(cmdCount.ExecuteScalar());

if ((recordCount % pageSize) > 0)
pageCount = recordCount / pageSize + 1;
else
pageCount = recordCount / pageSize;
OleDbCommand cmdRecord;
if (pageIndex == 1)//第一页
{
cmdRecord = new OleDbCommand(string.Format("select top {0} {1} from {2} {3} order by {4} ", pageSize, showString, myVw, whereString, orderString), m_Conn);
}
else if (pageIndex > pageCount)//超出总页数
{
cmdRecord = new OleDbCommand(string.Format("select top {0} {1} from {2} {3} order by {4} ", pageSize, showString, myVw, "where 1=2", orderString), m_Conn);
}
else
{
int pageLowerBound = pageSize * pageIndex;
int pageUpperBound = pageLowerBound - pageSize;
string recordIDs = recordID(string.Format("select top {0} {1} from {2} {3} order by {4} ", pageLowerBound, "ID", myVw, whereString, orderString), pageUpperBound);
cmdRecord = new OleDbCommand(string.Format("select {0} from {1} where id in ({2}) order by {3} ", showString, myVw, recordIDs, orderString), m_Conn);

}
OleDbDataAdapter dataAdapter = new OleDbDataAdapter(cmdRecord);
DataTable dt = new DataTable();
dataAdapter.Fill(dt);
ConnClose();
return dt;
}
}