模拟google分页效果

/// </summary>
    /// <param name="total">总记录数</param>
    /// <param name="per">每页记录数</param>
    /// <param name="page">当前页数</param>
    /// <param name="query_string">Url参数</param>
    private string pagination(int total, int per, int page, string query_string)
    {
        int allpage = 0;
        int next = 0;
        int pre = 0;
        int startcount = 0;
        int endcount = 0;
        string pagestr = "";

        if (page < 1) { page = 1; }
        //计算总页数
        if (per != 0)
        {
            allpage = (total / per);
            allpage = ((total % per) != 0 ? allpage + 1 : allpage);
            allpage = (allpage == 0 ? 1 : allpage);
        }
        next = page + 1;
        pre = page - 1;
        startcount = (page + 5) > allpage ? allpage - 9 : page - 4;//中间页起始序号
        //中间页终止序号
        endcount = page < 5 ? 10 : page + 5;
        if (startcount < 1) { startcount = 1; } //为了避免输出的时候产生负数，设置如果小于1就从序号1开始
        if (allpage < endcount) { endcount = allpage; }//页码+5的可能性就会产生最终输出序号大于总页码，那么就要将其控制在页码数之内
        pagestr = "共" + allpage + "页&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;";

        pagestr += page > 1 ? "<a href="" + query_string + "?page=1">首页</a>&nbsp;&nbsp;<a href="" + query_string + "?page=" + pre + "">上一页</a>" : "首页 上一页";
        //中间页处理，这个增加时间复杂度，减小空间复杂度
        for (int i = startcount; i <= endcount; i++)
        {
            pagestr += page == i ? "&nbsp;&nbsp;<font color="#ff0000">" + i + "</font>" : "&nbsp;&nbsp;<a href="" + query_string + "?page=" + i + "">" + i + "</a>";
        }
        pagestr += page != allpage ? "&nbsp;&nbsp;<a href="" + query_string + "?page=" + next + "">下一页</a>&nbsp;&nbsp;<a href="" + query_string + "?page=" + allpage + "">末页</a>" : " 下一页 末页";

        return pagestr;
    }