用datalist作分页，请帮我看看里面那里错误了。老是出现（未将对象引用设置到对象的实例：CurrentPage=(int)ViewState["CurrentPage"];

CurrentPage=(int)ViewState["StartIndex"];ViewState["StartIndex"]定义在哪了？

我找了很多例子都没有这个ViewState["StartIndex"]，搞了半天都搞不好！
请帮忙对其进行改正。

太麻烦了，用这个吧：http://www.webdiyer.com

第九行ViewState["CurrentPage"]=0;换成ViewState["PageIndex"] = 0;
第十一行CurrentPage=(int)ViewState["CurrentPage"];换成CurrentPage = (int)ViewState["PageIndex"];
试试看

第三十一行ViewState["CurrentPage"]=CurrentPage;
换成ViewState["PageIndex"] = CurrentPage;

<%@ Import Namespace="System.Data.OleDb"%>
<%@ Import Namespace="System.Data"%>
<HTML><HEAD><script language="C#" runat="server">
int PageSize, RecordCount,PageCount,CurrentPage;
public void Page_Load(object sender, System.EventArgs e){
PageSize=10;
if (!IsPostBack){
                           ViewState["CurrentPage"]=0;
                                    BindGrid();
                                    }
                                    }

void PagerButtonClick(object sender,CommandEventArgs e){
       PageCount=(int)ViewState["PageCount"];
//获得LinkButton的参数值
string arg=e.CommandName;
switch(arg)
{case "next":
if((int)ViewState["CurrentPage"]<(PageCount-1))
ViewState["CurrentPage"]=ViewState["CurrentPage"]+1;
break;
case "prev":
if((int)ViewState["CurrentPage"]>0)
CurrentPage--;
break;
case "last":
if((int)ViewState["CurrentPage"]<(PageCount-1));
ViewState["CurrentPage"]=(PageCount-1);
break;
case "first" :
ViewState["CurrentPage"]=0;
break;}
BindGrid();
}
   ICollection CreateDataSource(){
          int StartIndex;
          StartIndex=(int)ViewState(CurrentPage)*PageSize;
          CurrentPage=(int)ViewState["CurrentPage"];
string connstring=@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Inetpub\wwwroot\Ch0754\ch0754.mdb;Persist Security Info=False";
  string sql="select rowid,title,msgbody from CH0754 ";
  OleDbConnection conn=new OleDbConnection(connstring);
  OleDbDataAdapter da=new OleDbDataAdapter(sql,conn);
  DataSet ds=new DataSet();
  da.Fill(ds,(int)StartIndex,(int)PageSize,"try");
  return ds.Tables["try"].DefaultView;
}
public void BindGrid(){
DataList1.DataSource=CreateDataSource();
DataList1.DataBind();
                 }
</script>
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<FONT face="宋体">
<asp:datalist id="DataList1" runat="server">
<ItemTemplate>
<%# DataBinder.Eval(Container.DataItem,"rowid")%>
<%# DataBinder.Eval(Container.DataItem,"title")%>
</ItemTemplate>
</asp:datalist></FONT>
<P>
<asp:LinkButton id="btnFirst" runat="server" Text="首页" CommandName="first" ForeColor="navy" Font-Name="verdana"
Font-size="8pt" OnCommand="PagerButtonClick"></asp:LinkButton>
<asp:LinkButton id="btnPrev" runat="server" Text="前页" CommandName="prev" ForeColor="navy" Font-Name="verdana"
Font-size="8pt" OnCommand="PagerButtonClick"></asp:LinkButton>
<asp:LinkButton id="btnNext" runat="server" Text="后页" CommandName="next" ForeColor="navy" Font-Name="verdana"
Font-size="8pt" OnCommand="PagerButtonClick"></asp:LinkButton>
<asp:LinkButton id="btnLast" runat="server" Text="末页" CommandName="last" ForeColor="navy" Font-Name="verdana"
Font-size="8pt" OnCommand="PagerButtonClick"></asp:LinkButton></P>
</form>
</body>
</HTML>

case "prev":
if((int)ViewState["CurrentPage"]>0)
((int)ViewState["CurrentPage"]--;
break;

另外你的PageCount需要另外计算出来

改了很多，还是错误，我想应该是那个PageIndex出的错。我在网上找了很多这样的例子，其中多是大同小异，就是没有对PageIndex的处理。谁能说说啊！或者给个调试通过的。

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.Configuration;
using System.Web.Security;
using System.Data.SqlClient;namespace wshd.pricenews
{
/// <summary>
/// priceshow 的摘要说明。
/// </summary>
public class priceshow : System.Web.UI.Page
{
protected System.Web.UI.WebControls.LinkButton first;
protected System.Web.UI.WebControls.LinkButton prev;
protected System.Web.UI.WebControls.LinkButton next;
protected System.Web.UI.WebControls.LinkButton last;
protected System.Web.UI.WebControls.Label lblallcount;
protected System.Web.UI.WebControls.Label lblpagecount;
protected System.Web.UI.WebControls.Label lblcurrentindex;
protected System.Web.UI.WebControls.DataList DataList1;
protected System.Web.UI.WebControls.Button go;
    int PageSize,RecordCount,PageCount,CurrentPage;
protected System.Web.UI.WebControls.TextBox to;

private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
first.Text="首页";
prev.Text="前一页";
next.Text="下一页";
last.Text="尾页";
//分页分十页
PageSize = 2;
if(!IsPostBack)
{
CurrentPage = 0;
ViewState["PageIndex"] = 0;
//datalistkb();
ListBind(); }

//计算总共有多少记录
RecordCount = CalculateRecord();
lblallcount.Text = RecordCount.ToString();
//计算总共有多少页
PageCount = RecordCount/PageSize;
lblpagecount.Text = PageCount.ToString();
ViewState["PageCount"] = PageCount;
} #region Web Form Designer generated code
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.first.Click += new System.EventHandler(this.btnClick);
this.prev.Click += new System.EventHandler(this.btnClick);
this.next.Click += new System.EventHandler(this.btnClick);
this.last.Click += new System.EventHandler(this.btnClick);
this.go.Click += new System.EventHandler(this.go_Click);
this.Load += new System.EventHandler(this.Page_Load); }
#endregion
private void datalistkb()
{

SqlConnection cn=new SqlConnection(ConfigurationSettings.AppSettings["connectionString"]);
String strSQL="select * from pricenews";

SqlCommand cm=new SqlCommand(strSQL,cn);
// cm.Parameters.Add(new SqlParameter("@ID",SqlDbType.Int,10));
// cm.Parameters["@ID"].Value=Request.QueryString["ID"];
SqlDataAdapter da=new SqlDataAdapter(cm);
DataSet ds=new DataSet();
da.Fill(ds);
DataList1.DataSource=ds;
DataList1.DataBind();

}
//计算总共有多少条记录
public int CalculateRecord()
{
SqlConnection cn=new SqlConnection(ConfigurationSettings.AppSettings["connectionString"]);
int intCount;
cn.Open();
string strCount = "select count(*) as co from pricenews";
SqlCommand cm = new SqlCommand(strCount,cn);
SqlDataReader dr = cm.ExecuteReader();
if(dr.Read())
{
intCount = Int32.Parse(dr["co"].ToString());
}
else
{
intCount = 0;
}
cn.Close();
return intCount;
} private void btnClick(object sender, System.EventArgs e)
{
CurrentPage = (int)ViewState["PageIndex"];
PageCount = (int)ViewState["PageCount"];
             string cmd=((LinkButton)sender).CommandArgument;
// string cmd = e.CommandArgument;
//判断cmd，以判定翻页方向
switch(cmd)
{
case "first":
CurrentPage=0;
break;
case "next":
if(CurrentPage<(PageCount-1)) CurrentPage++;
break;
case "prev":
if(CurrentPage>0)
CurrentPage--;
break;
    case "last":
CurrentPage=PageCount-1;
break;
}

ViewState["PageIndex"] = CurrentPage;
ListBind();
    }
ICollection CreateSource()
{ int StartIndex;
            SqlConnection cn=new SqlConnection(ConfigurationSettings.AppSettings["connectionString"]);
//设定导入的起终地址
StartIndex = CurrentPage*PageSize;
string strSel = "select * from pricenews";
DataSet ds = new DataSet(); SqlDataAdapter da= new SqlDataAdapter(strSel,cn);
da.Fill(ds,StartIndex,PageSize,"pricenews"); return ds.Tables["pricenews"].DefaultView;
}
public void ListBind()
{
DataList1.DataSource = CreateSource();
DataList1.DataBind();

// lbnNextPage.Enabled = true;
// lbnPrevPage.Enabled = true;
// if(CurrentPage==(PageCount-1)) lbnNextPage.Enabled = false;
// if(CurrentPage==0) lbnPrevPage.Enabled = false;
lblcurrentindex.Text = (CurrentPage+1).ToString();

} private void go_Click(object sender, System.EventArgs e)
{

if(Convert.ToInt32(to.Text)>=1&&Convert.ToInt32(to.Text)<=PageCount)
{
CurrentPage=Convert.ToInt32(to.Text)-1;

}
else
{
CurrentPage=PageCount-1;
}
ListBind();

}

}
}

<%@ Page language="c#" Codebehind="priceshow.aspx.cs" AutoEventWireup="false" Inherits="wshd.pricenews.priceshow" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>priceshow</title>
<meta content="Microsoft Visual Studio 7.0" name="GENERATOR">
<meta content="C#" name="CODE_LANGUAGE">
<meta content="JavaScript" name="vs_defaultClientScript">
<meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="priceshow" method="post" runat="server">
<table cellSpacing="0" cellPadding="0" align="center" border="0">
<tr>
<td><asp:datalist id="DataList1" runat="server">
<ItemTemplate>
<table border="1" width="760" height="84" cellpadding="0" cellspacing="0" align="center">
<tr>
<td width="76%" height="18"><%#DataBinder.Eval(Container.DataItem,"title")%></td>
<td width="24%" height="18"><%#DataBinder.Eval(Container.DataItem,"date_time")%></td>
</tr>
<tr>
<td width="100%" height="16" colspan="2">
<table border="1" width="100%" height="108" cellpadding="0" cellspacing="0">
<tr>
<td width="94%" height="102"><%#DataBinder.Eval(Container.DataItem,"context")%></td>
</tr>
</table>
</td>
</tr>
<tr>
<td colspan="2">
<hr color="#333399">
</td>
</tr>
</table>
</ItemTemplate>
</asp:datalist></td>
</tr>
</table>
</TD></TR></TABLE>
<table cellSpacing="0" cellPadding="0" width="760" align="center" border="1">
<tr>
<td><FONT size="2">一共</FONT>
<asp:label id="lblallcount" ForeColor="#0000ff" Runat="server" Font-size="8pt" font-names="verdana"></asp:label><FONT size="2">条记录</FONT>
<FONT size="2">共</FONT>
<asp:label id="lblpagecount" runat="server" ForeColor="#0000ff" Font-Names="Verdana" Font-Size="8pt"></asp:label><FONT size="2">页</FONT>
<FONT size="2">第</FONT>
<asp:label id="lblcurrentindex" runat="server" ForeColor="#0000ff" Font-Names="Verdana" Font-Size="8pt"></asp:label><FONT size="2">页</FONT>
</td>
<td align="right"><asp:linkbutton id="first" runat="server" font-size="9pt" CommandArgument="first" ForeColor="#3300ff" Font-Names="Verdana"></asp:linkbutton> <asp:linkbutton id="prev" CommandArgument="prev" ForeColor="#3300ff" Font-Names="Verdana" Runat="server" Font-Size="9pt"></asp:linkbutton> <asp:linkbutton id="next" CommandArgument="next" ForeColor="#3300ff" Font-Names="Verdana" Runat="server" Font-Size="9pt"></asp:linkbutton> <asp:linkbutton id="last" CommandArgument="last" ForeColor="#3300ff" Font-Names="Verdana" Runat="server" Font-Size="9pt"></asp:linkbutton><FONT size="2">跳转到第
<asp:textbox onkeypress="return event.keyCode>=48&&event.keyCode<=57" onpaste="return !clipboardData.getData('text').match(/\D/)" id="to" ondragenter="return false" style="IME-MODE: disabled" runat="server" Width="28px" MaxLength="5"></asp:textbox></FONT>
<FONT size="2">页</FONT>
<asp:button id="go" Font-Names="Verdana" Runat="server" Text="GO" BackColor="WhiteSmoke"></asp:button></td>
</tr>
</table>
</form>
</body>
</HTML>

问题已经得到解决！我在此感谢donglicsdn(囡囡)以及caojingui(快乐的人) 。

调试易

用datalist作分页，请帮我看看里面那里错误了。老是出现（未将对象引用设置到对象的实例：CurrentPage=(int)ViewState["CurrentPage"];

解决方案 »