正文:大家都知道asp.net中的Gridview。datalist等都可以自定义分页,但是当你翻页的时候,数据表中的所有数据都会加载到内存,重新绑定,当然要是数据量小的话,这是可以的,我们也很乐意用,原因简单因为方便,但是要是数据量是999999999999……,在信息爆炸的这个时代海量数据是经常的时,那么这些控件自带的分页就显得有些……
解决这个问题办法就是自己动手
1.首先我是用存储过程来解决的,要弄懂这个问题,首先要从存储过程下手,代码如下:
CREATE proc getdataset
@TableList Varchar(200)='*',--搜索表的字段,比如:’id,datatime,job‘,用逗号隔开
@TableName Varchar(30), --搜索的表名
@SelectWhere Varchar(500)='',--搜索条件,这里不用写where,比如:job=’teacher‘and class='2'
@SelectOrderId Varchar(20),--表主键字段名。比如:id
@SelectOrder Varchar(200)='', --排序,可以使用多字段排序但主键字段必需在最前面.也可以不写,比如:order by class asc
@intPageNo int=1, --页号
@intPageSize int=10 ,--每页显示数
@RecordCount int OUTPUT --总记录数(存储过程输出参数)
as
declare @TmpSelect NVarchar(600)
declare @Tmp NVarchar(600)
set nocount on--关闭计数
set @TmpSelect = 'select @RecordCount = count(*) from '+@TableName+' '+@SelectWhere
execute sp_executesql
@TmpSelect, --执行上面的sql语句
N'@RecordCount int OUTPUT' , --执行输出数据的sql语句,output出总记录数
@RecordCount OUTPUT
if (@RecordCount = 0) --如果没有贴子,则返回零
return 0
/*判断页数是否正确*/
if (@intPageNo - 1) * @intPageSize > @RecordCount --页号大于总页数,返回错误
return (-1)
set nocount off--打开计数
if @SelectWhere != ''
begin
set @TmpSelect = 'select top '+str(@intPageSize)+' '+@TableList+' from '+@TableName+' where '+@SelectOrderId+' not in(select top '+str((@intPageNo-1)*@intPageSize)+' '+@SelectOrderId+' from '+@TableName+' '+@SelectWhere +' '+@SelectOrder+') and '+@SelectWhere +' '+@SelectOrder
end
else
begin
set @TmpSelect = 'select top '+str(@intPageSize)+' '+@TableList+' from '+@TableName+' where '+@SelectOrderId+' not in(select top '+str((@intPageNo-1)*@intPageSize)+' '+@SelectOrderId+' from '+@TableName+' '+@SelectOrder+') '+@SelectOrder
end
execute sp_executesql @TmpSelect
return(@@rowcount)
GO
其实代码也很简单,学编程的人基础上都是懂数据库的,这个存储过程估计不是问题。
其他的代码我都做了解释,有颜色的那段我没有解释,我在这里解释一下。其实也很简单,大家来看:
select top '+str((@intPageNo-1)*@intPageSize)+' '+@SelectOrderId+' from '+@TableName+' '+@SelectWhere +' '+@SelectOrder+'
这段代码的执行结果是什么了,是不是当前页前面的主键的集合啊,现在我们从所有的表中选出主键的值不在这个结果的之内的pagesize个记录不就是当前页的内容了吗?
2.aspx页面就不用再将了吧?我这里将代码写上:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="aa.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>无标题页</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" Height="180px" Width="867px">
<Columns>
<asp:BoundField DataField="job_id" HeaderText="job_id" />
<asp:BoundField DataField="job_desc" HeaderText="job_desc" />
<asp:BoundField DataField="max_lvl" HeaderText="max_lxl" />
</Columns>
</asp:GridView>
</div>
<asp:HyperLink ID="hylfirst" runat="server">首页</asp:HyperLink>
<asp:HyperLink ID="hylprev" runat="server">上一页</asp:HyperLink>
<asp:HyperLink ID="hylnext" runat="server">下一页</asp:HyperLink>
<asp:HyperLink ID="hylend" runat="server">尾页</asp:HyperLink>
第<asp:Label ID="lbRow" runat="server" Text="Label"></asp:Label>页,
共<asp:Label ID="lbpage" runat="server" Text="Label"></asp:Label>页,共<asp:Label
ID="lbRecord" runat="server" Text="Label"></asp:Label>条记录,转到<asp:TextBox ID="txtlink"
runat="server" Width="29px"></asp:TextBox>
页<asp:LinkButton ID="link" runat="server" OnClick="link_Click" TabIndex="1">转到</asp:LinkButton>
</form>
</body>
</html>
3.cs页面:
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
this.bind();
}
protected void link_Click(object sender, EventArgs e)
{
int page = Convert.ToInt32(txtlink.Text);
Response.Redirect("aa.aspx?CurrentPage="+page+"");
}
public void bind()
{
int sumPage;
int pageNo = 1;
int pageSize = 3;
if (Request.QueryString["CurrentPage"] == null)
{
pageNo = 1;
}
else
{
pageNo = Int32.Parse(Request.QueryString["CurrentPage"]);
}
SqlConnection conn = new SqlConnection(ConfigurationManager.AppSettings["ConStr"]);
SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = new SqlCommand();
da.SelectCommand.Connection = conn;
da.SelectCommand.CommandText = "getdataset";
da.SelectCommand.CommandType = CommandType.StoredProcedure;
da.SelectCommand.Parameters.Add("@TableList", SqlDbType.VarChar, 200).Value = "job_id,job_desc,max_lvl";
da.SelectCommand.Parameters.Add("@TableName", SqlDbType.VarChar, 30).Value = "jobs";
//da.SelectCommand.Parameters.Add("@SelectWhere", SqlDbType.VarChar, 500).Value = "where d=1";
da.SelectCommand.Parameters.Add("@SelectOrderId", SqlDbType.VarChar, 20).Value = "job_id";
da.SelectCommand.Parameters.Add("@SelectOrder", SqlDbType.VarChar, 200).Value = "order by min_lvl asc";
da.SelectCommand.Parameters.Add("@intPageNo", SqlDbType.Int).Value = pageNo;
da.SelectCommand.Parameters.Add("@intPageSize", SqlDbType.Int).Value = pageSize;
da.SelectCommand.Parameters.Add("@RecordCount", SqlDbType.Int).Direction = ParameterDirection.Output;
da.SelectCommand.Parameters.Add("RowCount", SqlDbType.Int).Direction = ParameterDirection.ReturnValue;
DataSet ds = new DataSet();
da.Fill(ds, "jobs");
GridView1.DataSource = ds;
GridView1.DataBind();
Int32 RecordCount = (Int32)da.SelectCommand.Parameters["@RecordCount"].Value; //求出总记录数,该值是output出来的值
Int32 RowCount = (Int32)da.SelectCommand.Parameters["RowCount"].Value; //求出当前页中的记录数,在最后一页不等于pagesize,
lbRecord.Text = RecordCount.ToString();
lbRow.Text = pageNo.ToString();
sumPage = (Int32)RecordCount / pageSize;
if (RecordCount % pageSize > 0)
{
sumPage = sumPage + 1;
}
lbpage.Text = sumPage.ToString();
if (pageNo > 1)
{
hylfirst.NavigateUrl = "aa.aspx?CurrentPage=1";
hylprev.NavigateUrl = string.Concat("aa.aspx?CurrentPage=", "", pageNo - 1);
}
else
{
hylprev.NavigateUrl = "";
hylfirst.NavigateUrl = "";
hylfirst.Visible = false;
hylprev.Visible = false;
}
if (pageNo < sumPage)
{
hylend.NavigateUrl = string.Concat("aa.aspx?CurrentPage=", "", sumPage);
hylnext.NavigateUrl = string.Concat("aa.aspx?CurrentPage=", "", pageNo + 1);
}
else
{
hylnext.NavigateUrl = "";
hylend.NavigateUrl = "";
hylend.Visible = false;
hylnext.Visible = false;
}
}
}