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using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Drawing;using System.Web;using System.Web.SessionState;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.HtmlControls;using System.Data.SqlClient;using System.Configuration;namespace WS.Webs
{
/**//// <summary>
/// WebForm1 的摘要说明。
/// </summary> public class WebForm1 : System.Web.UI.Page { protected System.Web.UI.WebControls.DataList datalist1; protected System.Web.UI.WebControls.Label LPageCount; protected System.Web.UI.WebControls.Label LRecordCount; protected System.Web.UI.WebControls.LinkButton Fistpage; protected System.Web.UI.WebControls.LinkButton Prevpage; protected System.Web.UI.WebControls.LinkButton Nextpage; protected System.Web.UI.WebControls.LinkButton Lastpage; protected System.Web.UI.WebControls.Label LCurrentPage; protected System.Web.UI.WebControls.TextBox gotoPage; //自定义分页码记录 const int PageSize=20; int PageCount,RecCount,CurrentPage,Pages,JumpPage;//定义几个保存分页参数变量 private void Page_Load(object sender, System.EventArgs e) { if(!Page.IsPostBack) { RecCount = Calc();//通过Calc()函数获取总记录数 PageCount = RecCount/PageSize + OverPage();//计算总页数（加上OverPage()函数防止有余数造成显示数据不完整） ViewState["PageCounts"] = RecCount/PageSize - ModPage();//保存总页参数到ViewState（减去ModPage()函数防止SQL语句执行时溢出查询范围，可以用存储过程分页算法来理解这句） ViewState["PageIndex"] = 0;//保存一个为0的页面索引值到ViewState ViewState["JumpPages"] = PageCount;//保存PageCount到ViewState，跳页时判断用户输入数是否超出页码范围 //显示LPageCount、LRecordCount的状态 LPageCount.Text = PageCount.ToString(); LRecordCount.Text = RecCount.ToString(); //判断跳页文本框失效 if(RecCount <= 20) gotoPage.Enabled = false; TDataBind();//调用数据绑定函数TDataBind()进行数据绑定运算 } } //计算余页 public int OverPage() { int pages = 0; if(RecCount%PageSize != 0) pages = 1; else pages = 0; return pages; } //计算余页，防止SQL语句执行时溢出查询范围 public int ModPage() { int pages = 0; if(RecCount%PageSize == 0 && RecCount != 0) pages = 1; else pages = 0; return pages; } /**//* *计算总记录的静态函数 *本人在这里使用静态函数的理由是：如果引用的是静态数据或静态函数，连接器会优化生成代码，去掉动态重定位项（对海量数据表分页效果更明显）。 *希望大家给予意见、如有不正确的地方望指正。 */ public static int Calc() { int RecordCount = 0; SqlCommand MyCmd = new SqlCommand("select count(*) as co from fdcproject",MyCon()); SqlDataReader dr = MyCmd.ExecuteReader(); if(dr.Read()) RecordCount = Int32.Parse(dr["co"].ToString()); MyCmd.Connection.Close(); return RecordCount; } //数据库连接语句（从Web.Config中获取） public static SqlConnection MyCon() { SqlConnection MyConnection = new SqlConnection(ConfigurationSettings.AppSettings["DSN2"]); MyConnection.Open(); return MyConnection; } private void TDataBind() { CurrentPage = (int)ViewState["PageIndex"];//从ViewState中读取页码值保存到CurrentPage变量中进行按钮失效运算 Pages = (int)ViewState["PageCounts"];//从ViewState中读取总页参数进行按钮失效运算 //判断四个按钮（首页、上一页、下一页、尾页）状态 if (CurrentPage + 1 > 1) { Fistpage.Enabled = true; Prevpage.Enabled = true; } else { Fistpage.Enabled = false; Prevpage.Enabled = false; } if (CurrentPage == Pages) { Nextpage.Enabled = false; Lastpage.Enabled = false; } else { Nextpage.Enabled = true; Lastpage.Enabled = true; } //数据绑定到DataList控件 DataSet ds = new DataSet(); //核心SQL语句，进行查询运算（决定了分页的效率:)） SqlDataAdapter MyAdapter = new SqlDataAdapter("Select Top "+PageSize+" * from fdcproject where projid not in(select top "+PageSize*CurrentPage+" projid from fdcproject order by projid asc) order by projid asc",MyCon()); MyAdapter.Fill(ds,"news"); datalist1.DataSource = ds.Tables["news"].DefaultView; datalist1.DataBind(); //显示Label控件LCurrentPaget和文本框控件gotoPage状态 LCurrentPage.Text = (CurrentPage+1).ToString(); gotoPage.Text = (CurrentPage+1).ToString(); //释放SqlDataAdapter MyAdapter.Dispose(); } Web 窗体设计器生成的代码#region Web 窗体设计器生成的代码 override protected void OnInit(EventArgs e) { // // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。 // InitializeComponent(); base.OnInit(e); } /**//// <summary> /// 设计器支持所需的方法 - 不要使用代码编辑器修改 /// 此方法的内容。 /// </summary> private void InitializeComponent() { this.Fistpage.Click += new System.EventHandler(this.Page_OnClick); this.Prevpage.Click += new System.EventHandler(this.Page_OnClick); this.Nextpage.Click += new System.EventHandler(this.Page_OnClick); this.Lastpage.Click += new System.EventHandler(this.Page_OnClick); this.gotoPage.TextChanged += new System.EventHandler(this.gotoPage_TextChanged); this.Load += new System.EventHandler(this.Page_Load); } #endregion private void gotoPage_TextChanged(object sender, System.EventArgs e) { try { JumpPage = (int)ViewState["JumpPages"];//从ViewState中读取可用页数值保存到JumpPage变量中 //判断用户输入值是否超过可用页数范围值 if(Int32.Parse(gotoPage.Text) > JumpPage || Int32.Parse(gotoPage.Text) <= 0) Response.Write("<script>alert('页码范围越界！');location.href='WebForm8.aspx'</script>"); else { int InputPage = Int32.Parse(gotoPage.Text.ToString()) - 1;//转换用户输入值保存在int型InputPage变量中 ViewState["PageIndex"] = InputPage;//写入InputPage值到ViewState["PageIndex"]中 TDataBind();//调用数据绑定函数TDataBind()再次进行数据绑定运算 } } //捕获由用户输入不正确数据类型时造成的异常 catch(Exception exp) { Response.Write("<script>alert('"+exp.Message+"');location.href='WebForm8.aspx'</script>"); } } private void Page_OnClick(object sender, System.EventArgs e) { CurrentPage = (int)ViewState["PageIndex"];//从ViewState中读取页码值保存到CurrentPage变量中进行参数运算 Pages = (int)ViewState["PageCounts"];//从ViewState中读取总页参数运算 string cmd = ((LinkButton)sender).CommandName; switch(cmd)//筛选CommandName { case "next": CurrentPage++; break; case "prev": CurrentPage--; break; case "last": CurrentPage = Pages; break; default: CurrentPage = 0; break; } ViewState["PageIndex"] = CurrentPage;//将运算后的CurrentPage变量再次保存至ViewState TDataBind();//调用数据绑定函数TDataBind() } }
}Trackback: http://tb.blog.csdn.net/TrackBack.aspx?PostId=935548
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