using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace test
{
    public partial class Form3 : Form
    {
        public int pageSize = 10;      //每页记录数
        public int recordCount = 0;    //总记录数
        public int pageCount = 0;      //总页数
        public int currentPage = 0;    //当前页

        public DataTable dtSource = new DataTable();


        public Form3()
        {
            InitializeComponent();
        }

        private void Form3_Load(object sender, EventArgs e)
        {
            //数据库操作获得DataTable
            string sql = "select ID,title from info";

            DB db = new DB();

            dtSource = db.GetDt(sql);
            //

            recordCount = dtSource.Rows.Count;

            pageCount = (recordCount / pageSize);

            if ((recordCount % pageSize) > 0)
            {
                pageCount++;
            }

            //默认第一页
            currentPage = 1;

            LoadPage();
        }

        private void LoadPage()
        {
            //
            if (currentPage < 1) currentPage = 1;
            if (currentPage > pageCount) currentPage = pageCount;
            //

            int beginRecord;
            int endRecord;
            DataTable dtTemp;

            dtTemp = dtSource.Clone();

            beginRecord = pageSize * (currentPage - 1);
            if (currentPage == 1) beginRecord = 0;
            endRecord = pageSize * currentPage;
            if (currentPage == pageCount) endRecord = recordCount;

            for (int i = beginRecord; i < endRecord; i++)
            {
                dtTemp.ImportRow(dtSource.Rows[i]);
            }

            dataGridView1.DataSource = dtTemp;

            label3.Text = currentPage.ToString();
            label5.Text = pageCount.ToString();
            label7.Text = recordCount.ToString();
            textBox1.Text = currentPage.ToString();
        }


        private void button1_Click(object sender, EventArgs e)
        {
            currentPage = 1;
            LoadPage();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            currentPage++;
            LoadPage();
        }
        private void button3_Click(object sender, EventArgs e)
        {
            currentPage--;
            LoadPage();
        }
        private void button4_Click(object sender, EventArgs e)
        {
            currentPage = pageCount;
            LoadPage();
        }

        private void button5_Click(object sender, EventArgs e)
        {
            int pageN = Convert.ToInt32(textBox1.Text);
            currentPage = pageN;
            LoadPage();
        }



    }
}