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

namespace Mini.Common
{
    public class PagerUtil
    {
        /// <summary>
        /// 设置分页信息
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="queryData"></param>
        /// <param name="pager"></param>
        public static void SetPager<T>(ref IQueryable<T> queryData, ref Pager pager)
        {
            //分页
            pager.totalRows = queryData.Count();
            if (pager.totalRows > 0)
            {
                if (pager.page <= 1)
                {
                    queryData = queryData.Take(pager.rows);
                }
                else
                {
                    queryData = queryData.Skip((pager.page - 1) * pager.rows).Take(pager.rows);//分页
                }
            }
        }

        public static DataTable SetPager(DataTable dt, ref Pager pager)
        {
            pager.totalRows = dt.Rows.Count;
            if (pager.page == 0) { return dt; }
            DataTable newdt = dt.Copy();
            newdt.Clear();
            int rowbegin = (pager.page - 1) * pager.rows;
            int rowend = pager.page * pager.rows;

            if (rowbegin >= dt.Rows.Count)
            { return newdt; }

            if (rowend > dt.Rows.Count)
            { rowend = dt.Rows.Count; }
            for (int i = rowbegin; i <= rowend - 1; i++)
            {
                DataRow newdr = newdt.NewRow();
                DataRow dr = dt.Rows[i];
                foreach (DataColumn column in dt.Columns)
                {
                    newdr[column.ColumnName] = dr[column.ColumnName];
                }
                newdt.Rows.Add(newdr);
            }
            return newdt;

        }
    }
}