通过后台绑定gridview的都有问题，通过前台添加数据源的，查询都没有问题，不知是何故？

并提示：

关键字 'and' 附近有语法错误。

这个是我的查询方法：

public void gv_bind()
{

int idbiaozhun = abcd;

string selesql = "select id_stu,stu_name,xiaozu_name, defen_dxbenke,defen_dxleiji,defen_xiaozudxbenke from jifen where id_biaozhun= " + idbiaozhun + "and id_jiaoshi=" + idjiaoshi + "and id_banji=" + idbanji+ "order by xiaozu_name desc";
DataSet ds = cc.ExceDS(selesql);
GridView1.DataSource = ds;
GridView1.DataKeyNames = new string[] { "id_stu" };
GridView1.DataBind();//将控件及其所有子控件绑定到指定的数据源
if (ds.Tables[0].Rows.Count == 0)
{
string sqlcharu_stu = "insert into jifen(id_jiaoshi,id_banji,id_stu,stu_name,id_fenzu,xiaozu_name) select id_jiaoshi,id_banji,id_stu,stu_name,id_fenzu,xiaozu_name from stu_user where stu_user.id_jiaoshi="+idjiaoshi+" and stu_user.id_banji="+idbanji;
string sqlset_biaozhun = "update jifen set id_biaozhun ="+idbiaozhun+" where id_jiaoshi=" + idjiaoshi + "and id_banji=" + idbanji + " and id_biaozhun is null ";

cc.ExecSQL(sqlcharu_stu);
cc.ExecSQL(sqlset_biaozhun);
DataSet dd = cc.ExceDS(selesql);
GridView1.DataSource = dd;

GridView1.DataKeyNames = new string[] { "id_stu" };
GridView1.DataBind();//将控件及其所有子控件绑定到指定的数据源
}


}

bacd是全局变量，通过点击控件的按钮获得，查询里，idjiaoshi，idbanji，从页面  protected void Page_Load(object sender, EventArgs e)里获得：

string idbanji= Session["jiaoshi_name"].ToString();
string idjiaoshi = Session["keti_name"].ToString();

当第一次运行时，没有任何问题，只要你不离开这个页面。当离开页面去做别的事情时，就会报错。

这个是 变量，abcd的取值方法：

protected void BulletedList1_Click(object sender, System.Web.UI.WebControls.BulletedListEventArgs e)
{
GridView3.Visible = false;
GridView2.Visible = false;
GridView1.Visible = true;

System.Web.UI.WebControls.ListItem li = BulletedList1.Items[e.Index];

abcd = Convert.ToInt16( li.Value);
//Response.Write("<script>alert('"+abcd+"')</script>");
gv_bind();
Response.Write("'" + abcd + "'");

}

每次查询时，页面都是可以得到abcd的。

对了，还有，我已经在web.config中，把Session的默认时间变为60分钟了。

问题报错：

“/pjxt”应用程序中的服务器错误。

关键字 'and' 附近有语法错误。

说明: 执行当前 Web 请求期间，出现未经处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。 

异常详细信息: System.Data.SqlClient.SqlException: 关键字 'and' 附近有语法错误。

源错误: 

源文件: f:\pjxt\pjxt\App_Code\DB.cs    行: 217 

堆栈跟踪: 

版本信息: Microsoft .NET Framework 版本:4.0.30319; ASP.NET 版本:4.0.30319.1

 前台绑定的数据查询就没有问题随时都能查到：

<asp:GridView ID="GridView3" runat="server" AllowSorting="True"
AutoGenerateColumns="False"
DataSourceID="SqlDataSource1" Visible="False" Width="837px">
<Columns>
<asp:BoundField DataField="id_stu" HeaderText="编号"
SortExpression="id_stu" />
<asp:BoundField DataField="stu_name" HeaderText="姓名"
SortExpression="stu_name" />
<asp:BoundField DataField="xiaozu_name" HeaderText="分组"
SortExpression="xiaozu_name" />
<asp:BoundField DataField="Column1" HeaderText="个人累计得分"
SortExpression="Column1" ReadOnly="True" />
<asp:BoundField DataField="defen_xiaozudxleiji" HeaderText="小组累计得分"
SortExpression="defen_xiaozudxleiji" />
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConflictDetection="CompareAllValues"
ConnectionString="<%$ ConnectionStrings:ktpjxtConnectionString %>"
DeleteCommand="DELETE FROM [jifen] WHERE [id_defen] = @original_id_defen AND (([id_jiaoshi] = @original_id_jiaoshi) OR ([id_jiaoshi] IS NULL AND @original_id_jiaoshi IS NULL)) AND (([id_keti] = @original_id_keti) OR ([id_keti] IS NULL AND @original_id_keti IS NULL)) AND (([id_fenzu] = @original_id_fenzu) OR ([id_fenzu] IS NULL AND @original_id_fenzu IS NULL)) AND (([id_banji] = @original_id_banji) OR ([id_banji] IS NULL AND @original_id_banji IS NULL)) AND (([xiaozu_name] = @original_xiaozu_name) OR ([xiaozu_name] IS NULL AND @original_xiaozu_name IS NULL)) AND (([id_biaozhun] = @original_id_biaozhun) OR ([id_biaozhun] IS NULL AND @original_id_biaozhun IS NULL)) AND (([id_stu] = @original_id_stu) OR ([id_stu] IS NULL AND @original_id_stu IS NULL)) AND (([stu_name] = @original_stu_name) OR ([stu_name] IS NULL AND @original_stu_name IS NULL)) AND (([defen_dxbenke] = @original_defen_dxbenke) OR ([defen_dxbenke] IS NULL AND @original_defen_dxbenke IS NULL)) AND (([defen_dxleiji] = @original_defen_dxleiji) OR ([defen_dxleiji] IS NULL AND @original_defen_dxleiji IS NULL)) AND (([defen_xiaozudxbenke] = @original_defen_xiaozudxbenke) OR ([defen_xiaozudxbenke] IS NULL AND @original_defen_xiaozudxbenke IS NULL)) AND (([defen_xiaozudxleiji] = @original_defen_xiaozudxleiji) OR ([defen_xiaozudxleiji] IS NULL AND @original_defen_xiaozudxleiji IS NULL)) AND (([defen_grheji] = @original_defen_grheji) OR ([defen_grheji] IS NULL AND @original_defen_grheji IS NULL))"
InsertCommand="INSERT INTO [jifen] ([id_jiaoshi], [id_keti], [id_fenzu], [id_banji], [xiaozu_name], [id_biaozhun], [id_stu], [stu_name], [defen_dxbenke], [defen_dxleiji], [defen_xiaozudxbenke], [defen_xiaozudxleiji], [defen_grheji]) VALUES (@id_jiaoshi, @id_keti, @id_fenzu, @id_banji, @xiaozu_name, @id_biaozhun, @id_stu, @stu_name, @defen_dxbenke, @defen_dxleiji, @defen_xiaozudxbenke, @defen_xiaozudxleiji, @defen_grheji)"
OldValuesParameterFormatString="original_{0}"
SelectCommand="select id_stu,stu_name,xiaozu_name ,sum(defen_dxleiji) ,defen_xiaozudxleiji from jifen where (([id_jiaoshi] = @id_jiaoshi) AND ([id_banji] = @id_banji)) group by xiaozu_name,stu_name,id_stu,defen_xiaozudxleiji ORDER BY xiaozu_name DESC

我把取到的值，放到  protected void Page_Load(object sender, EventArgs e)这里，有没有影响？

if (!IsPostBack)
{
string jiaoshiname = Session["jiaoshi_name"].ToString();
string ketiname = Session["keti_name"].ToString();
string banjiname = Session["banji_name"].ToString();
idjiaoshi = Session["id_jiaoshi"].ToString();
idbanji = Session["id_banji"].ToString();
idketi = Session["id_keti"].ToString();

}

问题的原因：是通过Session传到我的全局变量idjiaoshi，idbanji的值，丢失了，能有什么办法，留着这个值呢？

 又捣鼓了半天，还是这个问题？？？？

除了Session，页面传值是不是就没有这个问题呢？