mssql access top分页方法

mssql access top分页方法

双top法相比于not in和max法，就是可能传入一条sql语句来生成分页sql语句，也可多字段排序；

      然而无利也有弊，它要求排序字段必须造成惟一记载，且select后的字段列表中，不容许出现与排序字段同名的字段。

      只管sql2k5及以上版本已经提供了rownum()来停止分页解决，然而利用sql2k停止开发的还是较多的

using system;
using system.collections.generic;
using system.text;

/// <summary>
/// 结构分页后的sql语句
/// </summary>
public static class paginghelper
{
    /// <summary>
    /// 获取分页sql语句，排序字段需求造成惟一记载
    /// </summary>
    /// <param name="_recordcount">记载总数</param>
    /// <param name="_pagesize">每页记载数</param>
    /// <param name="_pageindex">以后页数</param>
    /// <param name="_safesql">sql查询语句</param>
    /// <param name="_orderfield">排序字段，多个则用“,”隔开</param>
    /// <returns>分页sql语句</returns>
    public static string createpagingsql(int _recordcount, int _pagesize, int _pageindex, string _safesql, string _orderfield)
    {
        //重新组合排序字段，防止有谬误
        string[] arrstrorders = _orderfield.split(new char[] { ',' }, stringsplitoptions.removeemptyentries);
        stringbuilder sboriginalorder = new stringbuilder(); //原排序字段
        stringbuilder sbreverseo教程rder = new stringbuilder(); //与原排序字段雷同，用于分页
        for (int i = 0; i < arrstrorders.length; i++)
        {
            arrstrorders[i] = arrstrorders[i].trim();  //去除前后空格
            if (i != 0)
            {
                sboriginalorder.append(", ");
                sbreverseorder.append(", ");
            }
            sboriginalorder.append(arrstrorders[i]);

int index = arrstrorders[i].indexof(" "); //判别能否有升降标识
            if (index > 0)
            {
                //交流升降标识，分页所需
                bool flag = arrstrorders[i].indexof(" desc", stringcomparison.ordinalignorecase) != -1;
                sbreverseorder.appendformat("{0} {1}", arrstrorders[i].remove(index), flag ? "asc" : "desc");
            }
            else
            {
                sbreverseorder.appendformat("{0} desc", arrstrorders[i]);
            }
        }

//计算总页数
        _pagesize = _pagesize == 0 ? _recordcount : _pagesize;
        int pagecount = (_recordcount + _pagesize - 1) / _pagesize;

//反省以后页数
        if (_pageindex < 1)
        {
            _pageindex = 1;
        }
        else if (_pageindex > pagecount)
        {
            _pageindex = pagecount;
        }