using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace DataListApplaction
{
    public partial class DataListDemo : System.Web.UI.Page
    {
        static PagedDataSource pds = new PagedDataSource();       //创建一个分页数据源的对象且一定要声明为静态
        //连接字符串
        SqlConnection connection = new SqlConnection(@"Data Source=.\CENA;Initial Catalog=Asp.net;Persist Security Info=True;User ID=sa;Password=123456");


        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                BindDataList(0);
            }
        }

        /// <summary>
        /// 实现数据分页
        /// </summary>
        /// <param name="currentpage"></param>
        private void BindDataList(int currentpage) 
        {
            pds.AllowPaging = true;       //允许分页
            pds.PageSize = 4;             //每页4条数据
            pds.CurrentPageIndex = currentpage; //当前页为传人的一个int类型
            string querySql = string.Format("SELECT * FROM dbo.Message");
            connection.Open();
            SqlDataAdapter sda = new SqlDataAdapter(querySql, connection);
            DataSet ds = new DataSet();
            //执行得到的数据放在数据集中
            sda.Fill(ds);
            //数据集中的数据放入到分页数据中
            pds.DataSource = ds.Tables[0].DefaultView;
            this.DataList1.DataSource = pds;
            this.DataList1.DataBind();
            connection.Close();
        }

        protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)
        {
            switch (e.CommandName)
            {
                //以下5个为 捕获用户点击 上一页 下一页等时发生的事件
                case "first"://第一页
                    pds.CurrentPageIndex = 0;
                    BindDataList(pds.CurrentPageIndex);
                    break;
                case "pre"://上一页
                    pds.CurrentPageIndex = pds.CurrentPageIndex - 1;
                    BindDataList(pds.CurrentPageIndex);
                    break;
                case "next"://下一页
                    pds.CurrentPageIndex = pds.CurrentPageIndex + 1;
                    BindDataList(pds.CurrentPageIndex);
                    break;
                case "last"://最后一页
                    pds.CurrentPageIndex = pds.PageCount - 1;
                    BindDataList(pds.CurrentPageIndex);
                    break;
                case "search"://页面跳转页
                    if (e.Item.ItemType == ListItemType.Footer)
                    {
                        int PageCount = int.Parse(pds.PageCount.ToString());
                        TextBox txtPage = e.Item.FindControl("txtPage") as TextBox;
                        int MyPageNum = 0;
                        if (!txtPage.Text.Equals(""))
                            MyPageNum = Convert.ToInt32(txtPage.Text.ToString());
                        if (MyPageNum <= 0 || MyPageNum > PageCount)
                            Response.Write("<script>alert(‘请输入页数并确定没有超出总页数！‘)</script>");
                        else
                            BindDataList(MyPageNum - 1);
                    }
                    break;
            }

        }
        protected void DataList1_ItemDataBound(object sender, DataListItemEventArgs e)
        {
            if (e.Item.ItemType == ListItemType.Footer)
            {
                //以下六个为得到脚模板中的控件,并创建变量.
                Label CurrentPage = e.Item.FindControl("labCurrentPage") as Label;
                Label PageCount = e.Item.FindControl("labPageCount") as Label;
                LinkButton FirstPage = e.Item.FindControl("lnkbtnFirst") as LinkButton;
                LinkButton PrePage = e.Item.FindControl("lnkbtnFront") as LinkButton;
                LinkButton NextPage = e.Item.FindControl("lnkbtnNext") as LinkButton;
                LinkButton LastPage = e.Item.FindControl("lnkbtnLast") as LinkButton;
                CurrentPage.Text = (pds.CurrentPageIndex + 1).ToString();//绑定显示当前页
                PageCount.Text = pds.PageCount.ToString();//绑定显示总页数
                if (pds.IsFirstPage)//如果是第一页,首页和上一页不能用
                {
                    FirstPage.Enabled = false;
                    PrePage.Enabled = false;
                }
                if (pds.IsLastPage)//如果是最后一页"下一页"和"尾页"按钮不能用
                {
                    NextPage.Enabled = false;
                    LastPage.Enabled = false;
                }
            }
        }
    }
}